Processing apparatus with pressure control and gas recirculation system

ABSTRACT

A processing apparatus includes a sealed vacuum chamber which contains a processing portion; a pressure controlling system which keeps the internal pressure of the sealed vacuum chamber constant at a predetermined level by exhausting the ambient gas in the sealed vacuum chamber; and an ambient gas recirculating system which recirculates the ambient gas exhausted from the sealed vacuum chamber back into the sealed vacuum chamber; wherein the ambient gas recirculated by the ambient gas recirculating system is blown into the sealed vacuum chamber so that a gas flow is generated in a predetermined direction along the processing portion.

FIELD OF THE INVENTION AND RELATED ART

The present invention relates to a processing apparatus equipped with asealed vacuum device which contains a processing portion. In particular,it relates to a processing apparatus suitable for the manufacture of asemiconductor element, or the like. It also relates to a devicemanufacturing method which employs such a processing apparatus.

In the manufacture of a semiconductor element or the like, an exposingapparatus is used. As semiconductor elements have been renderedmicroscopic and highly integrated, X-ray has come to attract attentionas one of the most promising choices of exposing light. The rate of theX-ray attenuation caused by the presence of the atmospheric air isextremely high. Therefore, when an X-ray is used as the exposure beamfor a semiconductor exposing apparatus, the X-ray is guided into anexposure chamber through a beam duct which has been evacuated to anextremely high degree. In an exposure chamber, a substrate positioningstage and a mask holding apparatus are placed. A substrate positioningstage accurately positions a piece of substrate wafer or the like withthe use of a chuck activated by suction. A mask holding apparatus holdsa mask. In order to accurately expose the predetermined area of a pieceof substrate by an exposure beam, the substrate piece must be veryaccurately positioned. Therefore, a laser interferometry based measuringdevice, or the like, is placed in an exposure chamber to measure theposition of the substrate positioning stage in the chamber. In order toprevent X-ray attenuation, the atmospheric air in an exposure chamber isevacuated, creating a virtual vacuum chamber, while filling theevacuated exposure chamber with a small amount helium gas or the like toenhance the heat dissipation from the substrate in the wafer form, or amask. Further, an exposure chamber is structured so that the pattern ofthe mask held by a mask holding apparatus is transferred onto thesubstrate by the X-ray as exposure light.

The internal pressure of an exposure chamber, or a vacuum chamber,affects the amount of X-ray transmission through the chamber. In otherwords, the change in the internal pressure of the vacuum chamber causesnonuniform exposure. The vacuum level falls as the atmospheric air, thegases from the bearings or the like, of the aforementioned positioningstage or the like, leak into the vacuum chamber, which in turn reducesthe amount of the X-ray transmission through the internal space of thevacuum chamber. In other words, this kind of vacuum loss in an exposurechamber, or a vacuum chamber, is one of the main reasons why theperformance of an exposing apparatus deteriorates in accuracy, and alsowhy the throughput of an exposure apparatus reduces. Further, theinternal temperature of a vacuum chamber locally increases due to theheat sources contained in the vacuum chamber, for example, the actuatoror electrical wiring of the substrate positioning stage, the laser, orthe like. Also, the internal temperature of the vacuum chamber islocally increased by the heat from the exposure light projected onto thesubstrate wafer and the mask. This kind of local temperature increasedeforms the mask and the substrate, making it impossible to desirablytransfer the mask pattern. In addition, the local temperaturefluctuation creates a turbulence in the ambience gas in the measurementpath of the laser beam projected by the laser interferometry basedmeasuring device in the vacuum chamber, which results in fluctuation inthe refractive index of this portion of the ambience gas. Thefluctuation of the refractive index makes it impossible to accuratelymeasure the position of the substrate positioning device with the use ofa laser interferometry based measuring device. Thus, the pressure,temperature, and degree of purity of the gas in an exposure chamber, ora vacuum chamber, must be very precisely controlled as is evident fromthe above explanation.

Thus, the air in an exposure chamber, that is, a sealed container, isreplaced with a small amount of inert gas such as pure helium, so thatthe internal space of the exposure chamber becomes a virtual vacuumspace. Known as a method for keeping the gas in the exposure chamberpure while maintaining the internal space of the exposure chamber in thevirtual vacuum state is the method disclosed in U.S. Pat. No. 5,267,292,which corresponds to EP application no. 363,168, for example. Accordingto this patent, the internal pressure of the exposure chamber, or thesealed container, is kept constant by adjusting the flow rate at whichthe ambient gas in the exposure chamber is exhausted from the exposurechamber, and the flow rate at which very pure gas is allowed to flowinto the exposure chamber, based on the internal pressure of theexposure chamber detected with the use of a pressure sensor. In thiscase, the flow rate at which the pure gas is allowed to flow into theexposure chamber is a certain number of times the flow rate at whichunwanted gases flow into the exposure chamber.

Further, the following technology is disclosed in Japanese Laid-OpenPatent Application No. 156625/1990. Thus, according to this patent, asealed chamber is employed as an exposure chamber in which X-ray is usedas exposure light. In operation, the atmospheric air in the sealedchamber is evacuated, and is replaced with a small amount of gas, forexample, helium gas. As for the operational fluid for the staticpressure bearings for the positioning stage in the evacuated sealedchamber (hereinafter, “vacuum chamber”), the ambient gas, that is,helium gas, in the vacuum chamber is used; the ambient gas is fed to thestatic pressure bearing after its pressure is increased with the use acompressor. The internal pressure of the vacuum chamber is controlled byadjusting the flow rate at which the helium gas, or the ambient gas, inthe vacuum chamber is exhausted. More specifically, the internalpressure of the vacuum chamber is detected, and the flow rate at whichthe ambient gas in the vacuum chamber is exhausted by a vacuum pump isadjusted in response to the detected internal pressure of the vacuumchamber, so that the internal pressure of the vacuum chamber remainsvirtually constant. The helium gas suctioned out of the vacuum chamberby the vacuum pump is recirculated into the vacuum chamber to reducehelium gas consumption, while keeping constant the purity of the heliumgas in the vacuum chamber so that exposure does not become uneven.

Japanese Laid-Open Patent Application No. 264404/1996 also discloses anambient gas recirculating system. According to this patent, the ambientgas in a vacuum chamber is suctioned out by a vacuum pump, so that theinternal pressure of the vacuum chamber remains constant at apredetermined level. The ambient gas suctioned out of the vacuum chamberis compressed by a compressor, and stored in a tank. Then, this ambientgas compressed and stored in the tank is recirculated into the vacuumchamber after being purified by a gas purifier, so that the rate atwhich ambient gas such as helium gas, which is rather expensive, isutilized, is improved, reducing thereby the cost for running theapparatus.

There is a technology for controlling the internal environment, of asemiconductor exposing apparatus, the ambient gas of which is theatmospheric air. According to this technology, the chamber in which anexposing apparatus is placed is connected to an air conditioningapparatus, which prevents the internal temperature of the chamber frombeing increased by the heat sources, for example, a mechanical powersource such as a motor, electrical wiring, a laser, and the like, in thechamber, so that the internal temperature of the chamber remainsconstant at a predetermined level. This type of air conditioningapparatus is constituted of a fan, and a heat exchanger such as a heateror a cooler. It takes in the air from within a chamber or theatmospheric air, adjusts the temperature of the air by the heatexchanger, and sends the air into the chamber by the fan through theintake opening of the chamber. In other words, it controls thetemperature of the ambient air in the chamber by circulating the airthrough a predetermined path, so that the temperature of the ambient airin the chamber does not fluctuate, and does not becomes uneven. Further,the dust in the air is removed by a filter disposed in the aircirculation path so that the cleanliness of the chamber is controlled.

However, the above described exposure chamber based on the conventionaltechnologies has a problem, even though it can reduce unevenness intemperature in the chamber by eliminating local temperature increase,and therefore, the ambient gas in the chamber is prevented from becomingturbulent. The problem is, if the fan of the air conditioner is disposedmore than a certain distance away from the exposing portion, thevelocity of the down flow created in the chamber does not reach apredetermined velocity, and therefore, the fan must be disposedimmediately adjacent to the exposing portion. If the fan is placedimmediately adjacent to the exposing portion, the vibration generated bythe fan is transmitted through the plumbing or the like, causing thepositioning stage or mask holding apparatus of the exposing portion tovibrate, even if the fan is not directly in contact with the exposingportion. The vibration of the stage or the like causes the positionalrelationship between a substrate and a mask to vary, making the linewidth of the pattern which will be formed on the substrate, differentfrom the predetermined line width of a mask. Also, the vibration reducesresolution. Further, the driving portion of the fan generates a largeamount of heat, and therefore, it must be cooled by providing it withthe plumbing for water cooling. Provision of such plumbing, whichrequires a space for the plumbing, increases the size. or the footprint, of each exposing apparatus, reducing the number of exposingapparatuses which can be placed in each floor. This results in costincrease. In addition, if this type of air conditioning apparatus isdisposed in a ambient vacuum, the lubricant in the rotational portionsof the fan evaporates into the ambient vacuum, extremely reducing thedurability of the fan. Thus, it is not desirable to place an airconditioning apparatus, which uses a fan, in a vacuum chamber in whichthere is an exposing apparatus, the exposing light of which is X-ray.

Technologies, such as the above described, for controlling the pressure,temperature, and purity of the ambient gas in a vacuum chamber whichcontains an exposing apparatus, to prevent the attenuation of X-ray, hasbeen long known. However, those technologies suffer from problems. Thatis, they do not actively generate flows in the ambient gas in a vacuumchamber. Therefore, they fail to enhance the dissipation of the heatgenerated by the irradiation of the exposure light upon a substrate or amask failing to prevent the temperature increase in the vacuum chamber.Also, they fail to sufficiently remove the heat generated by the otherheat sources, for example, the driving means and electric wiring of thepositioning stage, laser, and the like, in the vacuum chamber.Consequently, the temperature in the vacuum chamber locally increases orvaries, which results in uneven exposure. In addition, the mask or thesubstrate is deformed by the heat generated by the exposure light. Inother words, these technologies fail to achieve a high level ofpreciseness in pattern transferring.

Further, as described above, in order to precisely position a substrate,a laser interferometry based measuring device is used for measuring theposition of the substrate positioning stage in the vacuum chamber inwhich an exposing apparatus is disposed. If a turbulence is generated inthe. measurement path of the laser beam projected by the measuringapparatus, by the aforementioned heat, the reflective index of theambient gas in the path varies, which causes measurement errors. Thisdecreases preciseness in substrate positioning. Thus, the occurrence ofturbulence in the ambient gas in the vacuum chamber, which adverselyaffects the accuracy of a laser interferometry based measuring device,must be prevented, so that the environment in the vacuum chamber remainsstable.

Elaborating further on the reflective index of a laser beam in theatmospheric air in the normal stage; if the temperature changes 1° C.,the reflective index changes by approximately 1 ppm. This change in thereflective index causes an error in the measurement by a laserinterferometry based measuring device. For example, if the true distancefrom the laser interferometry based measuring device to the stage is 500mm, a temperature change of 1° C. causes a measurement error of 500 nm,or 1 ppm of 500 mm. Since the accuracy in aligning a mask with asubstrate is required to be no more than 10 nm, the accuracy of theinterferometer for measuring the position of the stage must be no morethan 5 nm. Thus, in order to reduce the measurement error of theinterferometer, the temperature fluctuation in the measurement lightpath of the interferometer should be kept within approximately 0.01° C.The reflective index fluctuation caused by temperature fluctuation in ahelium filled chamber with an internal pressure of one fifth theatmospheric air pressure is approximately one fortieth the reflectiveindex in an exposure chamber filled with an atmospheric air with thenormal pressure. However, the temperature fluctuation should be keptwithin approximately 0.4° C. Even under this kind of condition, in orderto keep the measurement error of the interferometer below 2.5 nm toimprove alignment accuracy, the temperature fluctuation must be keptwithin 0.2° C. However, the vacuum chamber contains heat sources, thatis, the driving means and wiring for the positioning stage, laser, andthe like. They warm up the ambient gas adjacent to them, and the warmedambient gas sometimes drifts into the measurement light path of theinterferometer, causing the interferometer to be inaccurate.

A vacuum chamber, which contains a processing portion such as anexposing apparatus, also contains a substrate positioning stage foraccurately positioning a substrate. The substrate positioning stage isprovided with a suction chuck for holding a substrate. This type ofchuck is connected to a vacuum pump, which is disposed outside thevacuum chamber, and is activated to maintain a certain amount of suctionto keep a substrate held to the suction chuck of the substratepositioning stage. Thus, each time the vacuum pump is activated, acertain amount of the ambient gas in the vacuum chamber is exhaustedthrough the suction chuck, and therefore, the internal pressure of thevacuum chamber temporarily decreases. In other words, exhausting theambient gas in the vacuum chamber by the vacuum pump for the suctionchuck occurs every time a substrate is held to the positioning stage bysuction. In the case of a vacuum chamber based on the, prior technology,a certain amount of fresh ambient gas is added to the vacuum chamber.However, this supply of fresh ambient gas is for compensating for theleak of the atmospheric air into the vacuum chamber. In other words, itis not added in consideration of the loss of the ambient gas caused bythe vacuum pump for the suction chuck. Therefore, if a processingapparatus is operated for a long period of time, the amount of theambient gas in the vacuum chamber exhausted by the vacuum pump for thesuction chuck becomes too large to be compensated for by the certainamount of fresh ambient gas added to the vacuum chamber to compensatefor the aforementioned leak of the atmospheric air into the vacuumchamber. Consequently, the internal pressure of the vacuum chambergradually decreases in spite of the addition of the aforementioned freshsupply of ambient gas; it is possible that the internal pressure of thevacuum chamber cannot be accurately controlled. If the internal pressureof the vacuum chamber cannot be accurately controlled, X-raytransmittance is adversely affected, resulting in uneven exposure. Inother words, exposure accuracy deteriorates, which is one of theessential problems in the prior technologies.

Also in the cases of the above described prior technologies, the ambientgas in a vacuum chamber is suctioned out to maintain the internalpressure of the vacuum chamber at a predetermined vacuum level. Then,the ambient gas suctioned out of the vacuum chamber is purified, andrecirculated into the vacuum chamber, improving the rate at which heliumgas, that is, expensive ambient gas, is utilized during the operation ofa processing apparatus. This reduces the consumption of the expensiveambient gas, reducing thereby the cost for running the apparatus.However, when it is necessary to stop the apparatus for the maintenanceof a semiconductor exposing apparatus or the like disposed in the vacuumchamber, or at the end of an operation, first the ambient gas in thevacuum chamber is released into the atmosphere from the vacuum chamberor the ambient gas recirculating system. Next, the vacuum chamber isfilled with nitrogen gas or air with the normal pressure. Then, themaintenance operation is carried out, or the apparatus is completelystopped. In other words, each time the apparatus is stopped formaintenance or the like, helium gas as the ambient gas for the vacuumchamber, which is rather expensive, is released into the atmosphere.Therefore, the prior technologies could not reduce helium gasconsumption; they could not reduce the cost for running a processingapparatus.

SUMMARY OF THE INVENTION

The present invention is made in consideration of the above describedproblems which must be solved. The primary object of the presentinvention is to provide a processing apparatus, the internal ambience ofwhich is stable. This is accomplished by creating a flow of the ambientgas in a predetermined direction in the sealed vacuum chamber of theprocessing apparatus to eliminate the unevenness in the internaltemperature of the sealed vacuum chamber while preventing the ambientgas in the vacuum chamber from becoming turbulent.

Another object of the present invention is to provide a processingapparatus, the internal pressure of the sealed vacuum container of whichis controlled with higher accuracy. This is accomplished by effectivelycompensating for the decrease in the internal pressure of the sealedvacuum chamber.

Another object of the present invention is to provide a processingapparatus which consumes a much smaller amount of ambient gas, andtherefore, costs less to run, compared to conventional apparatus. Thisis accomplished by storing the ambience gas in its sealed vacuumcontainer, in the ambient gas recirculating system before stopping theapparatus.

Another object of the present invention is to provide a devicemanufacturing method which employs a processing apparatus such as thosedescribed above.

A processing apparatus according to the present invention foraccomplishing at least one of the above described objects ischaracterized in that it comprises:

a sealed vacuum chamber which contains a processing portion;

a pressure controlling system which keeps the internal pressure of thesealed vacuum chamber constant at a predetermined level by exhaustingthe ambient gas in the sealed vacuum chamber;

and an ambience gas recirculating system which recirculates the ambientgas exhausted from the sealed vacuum chamber back into the sealed vacuumchamber; and

wherein the ambience gas recirculated by the ambience gas recirculatingsystem is blown into the sealed vacuum chamber so that a gas flow isgenerated in a predetermined direction along the aforementionedprocessing portion.

Regarding the above processing apparatus, it is desired that ambient gasin the sealed vacuum chamber is exhausted by a pump or a compressor;

the ambient gas recirculated by the ambient gas recirculating system isblown into the sealed vacuum chamber through an intake orifice disposedin the top portion of the sealed vacuum chamber, so that a downward gasflow is generated toward an exhaust orifice disposed in the bottomportion of the sealed vacuum chamber;

the ambient gas recirculated by the ambient gas recirculating system isblown into the sealed vacuum chamber, toward the light path of the laserinterferometry based measuring device disposed in the sealed vacuumchamber;

a certain portion of the ambient gas recirculated by the ambient gasrecirculating system is blown into the sealed vacuum chamber through theintake orifice disposed in the top portion of the sealed vacuum chamber,so that a downward gas flow is generated toward an exhaust orificedisposed in the bottom portion of the sealed vacuum chamber, while therest of the gas recirculated by the gas recirculating system is blowninto the vacuum chamber, toward the light path of the laserinterferometry based measuring device disposed in the sealed vacuumchamber;

the ambient gas recirculating system is provided with a chemical filter,which is located where the ambient pressure is equal to, or greaterthan, the atmospheric air pressure:

the ambient gas recirculating system is provided with a temperaturecontrol portion for adjusting the temperature of the ambient gas;

a sensor for measuring the temperature of the ambience gas is disposedat the intake orifice, and the temperature control portion is controlledin response to the results of the measurement by the sensor;

a portion of the ambient gas recirculating system which exhausts theambient gas in the sealed vacuum chamber is constituted of two ambientgas recirculating branches, and a valve for controlling the ambient gasflow rate is connected into the branch with the smaller flow rate;

the processing portion contained in the sealed vacuum chamber is anexposing apparatus for substrate exposure.

The second processing apparatus in accordance with the present inventionfor accomplishing one of the aforementioned objects is characterized inthat it comprises:

a sealed vacuum chamber which contains a processing portion; and

an ambient gas recirculating system which exhausts the ambient gas inthe sealed vacuum chamber, increases the pressure of the exhausted gas,and recirculates it into the vacuum chamber, with the use of acompressor or a pump;

wherein the ambient gas recirculated by the ambient gas recirculatingsystem is blown into the sealed vacuum chamber so that a gas flow isgenerated in a predetermined direction, adjacent to the aforementionedprocessing portion.

Regarding the above processing apparatus, it is desired that the ambientgas recirculated by the ambience gas recirculating system is blow intothe sealed vacuum chamber through an intake orifice disposed in the topportion of the sealed vacuum chamber, so that a downward gas flow isgenerated toward an exhaust orifice disposed in the bottom portion ofthe sealed vacuum chamber;

the ambient gas recirculated by the ambient gas recirculating system isblow into the sealed vacuum chamber, toward the light path of the laserinterferometry based measuring device disposed in the sealed vacuumchamber;

a certain portion of the ambient gas recirculated by the ambience gasrecirculating system is blown into the sealed vacuum chamber through theintake orifice disposed in the top portion of the sealed vacuum chamber,so that a downward gas flow is generated toward an exhaust orificedisposed in the bottom portion of the sealed vacuum chamber, while therest of the gas recirculated by the gas recirculating system is blowninto the vacuum chamber, toward the light path of the laserinterferometry based measuring device disposed in the sealed vacuumchamber;

the ambient gas recirculating system is provided with a chemical filter,which is located where the ambient pressure is equal to, or greaterthan, the atmospheric air pressure;

the ambient gas recirculating system is provided with a temperaturecontrol portion for adjusting the temperature of the ambient gas;

a sensor for measuring the temperature of the ambient gas is disposed atthe intake orifice, and the temperature control portion is controlled inresponse to the results of the measurement by the sensor;

a portion of the ambient gas recirculating system which exhausts theambient gas in the sealed vacuum chamber is constituted of two ambiencegas recirculating branches, and a valve for controlling the ambient gasflow rate is connected into the branch with the smaller flow rate;

the processing portion contained in the sealed vacuum chamber is anexposing apparatus for substrate exposure.

The third processing apparatus in accordance with the present inventionfor accomplishing one of the aforementioned object is characterized inthat it comprises:

a sealed vacuum chamber which contains a processing portion;

a pressure controlling system which keeps the internal pressure of thesealed vacuum chamber constant at a predetermined level by exhaustingthe ambient gas in the sealed vacuum chamber;

an ambient gas recirculating system which increases the pressure of theambient gas exhausted from the sealed vacuum chamber, and recirculatesthis exhausted ambient gas with the increased pressure into the sealedvacuum chamber; and

an ambient gas supplying device for adding ambient gas to the sealedvacuum chamber.

Regarding the above processing apparatus, it is desired that thepressure controlling system comprises:

a valve for controlling the flow rate of the ambience gas;

a pump or a compressor;

a pressure sensor for detecting the internal pressure of the vacuumchamber; and

a controller which controls the ambient gas flow rate control valve inresponse to the results of the measurement by the pressure sensor;

the ambient gas recirculating system comprises:

a tank for storing the ambience gas exhausted by the pump or compressor;and

a flow rate control portion or a regulator for recirculating the ambientgas stored in the tank, into the sealed vacuum chamber;

the ambient gas recirculating system is provided with a chemical filter,which is located where the ambient pressure is equal to, or greaterthan, the atmospheric air pressure;

the ambient gas recirculating system is provided with a temperaturecontrol portion for adjusting the temperature of the ambient gas;

a sensor for measuring the temperature of the ambience gas is disposedat the intake orifice, and the temperature control portion is controlledin response to the results of the measurement by the sensor;

a portion of the ambient gas recirculating system which exhausts theambient gas in the sealed vacuum chamber is constituted of two ambientgas recirculating branches, and a valve for controlling the ambient gasflow rate is connected into the branch with the smaller flow rate;

the processing portion contained in the sealed vacuum chamber is anexposing apparatus for substrate exposure.

The fourth processing apparatus in accordance with the present inventionfor accomplishing one of the aforementioned object is characterized inthat it comprises:

a sealed vacuum chamber which contains a processing portion;

a pressure controlling system which keeps the internal pressure of thesealed vacuum chamber constant at a predetermined level by exhaustingthe ambient gas in the sealed vacuum chamber; and

an ambient gas recirculating system which recirculates the ambient gasexhausted from the sealed vacuum chamber, back into the sealed vacuumchamber; and

a high pressure ambient gas recirculating system which increases thepressure of the ambient gas exhausted from the sealed vacuum chamber,and recirculates this ambient gas with the increased pressure into thesealed vacuum chamber.

Regarding the above apparatus, it is desired that the apparatuscomprises:

an ambient gas supply system for adding ambient gas to the sealed vacuumchamber;

the pressure controlling system comprises:

a valve for controlling the flow rate of the ambient gas;

a pump or a compressor;

a pressure sensor for detecting the internal pressure of the vacuumchamber; and

a controller which controls the ambient gas flow rate control valve inresponse to the results of the measurement by the pressure sensor;

the ambient gas recirculating system comprises a tank for storing theambient gas exhausted by the pump or compressor, and a flow rate controlportion, and recirculates the ambient gas stored in the tank into thesealed vacuum chamber at a predetermined flow rate through the flow ratecontrol portion; and

the high pressure ambient gas recirculating system comprises: a highpressure tank for storing the ambient gas exhausted by the pump orcompressor and then highly compressed; and a regulator whichrecirculates the high pressure ambient gas to the sealed vacuum chamberwhile allowing the gas to decompress;

the ambient gas recirculating system comprises a control valve whichcontrols the gas flow rate of the ambient gas recirculating system inresponse to the results of the measurement of a pressure sensor formeasuring the internal pressure of the tank in the ambient gasrecirculating system;

the control valve adds ambience gas to the tank, or suctions out theambient gas in the tank;

a pump for activating a suction chuck contained in the sealed vacuumchamber is connected into the ambient gas recirculating system;

at least one of the ambient gas recirculating system or high pressureambient gas recirculating system, or both, are provided with a chemicalfilter, which is located where the ambient pressure is equal to, orgreater than, the atmospheric air pressure;

at least one of the ambient gas recirculating system or high pressureambient gas recirculating system, or both, are provided with atemperature control portion for adjusting the temperature of the ambientgas;

a sensor for measuring the temperature of the ambience gas is disposedat the intake orifice, and the temperature control portion is controlledin response to the results of the measurement by the sensor;

a portion of the ambient gas recirculating system which exhausts theambient gas in the sealed vacuum chamber is constituted of two ambientgas recirculating branches, and a valve for controlling the ambient gasflow rate is connected into the branch with the smaller flow rate;

the processing portion contained in the sealed vacuum chamber is anexposing apparatus for substrate exposure.

The fifth processing apparatus in accordance with the present inventionfor accomplishing one of the aforementioned objects is characterized inthat it comprises:

a sealed vacuum chamber which contains a processing portion;

a pressure controlling system which keeps the internal pressure of thesealed vacuum chamber constant at a predetermined level by exhaustingthe ambient gas in the sealed vacuum chamber;

an ambient gas recirculating system which recirculates the ambient gasexhausted from the sealed vacuum chamber back into the sealed vacuumchamber; and

a high pressure ambience gas recirculating system which increases theambient gas exhausted from the sealed vacuum chamber, and recirculatesthis ambient gas with the high pressure into the sealed vacuum chamber;

wherein before the processing apparatus is stopped, at least a portionof the ambience gas is stored in at least one of the ambient gasrecirculating system or high pressure ambient gas recirculating system,or both.

Regarding the above processing apparatus, it is desired that theapparatus also comprises:

an ambient gas supplying system for adding ambient gas to the sealedvacuum chamber;

the pressure controlling system comprises:

a valve for controlling the flow rate of the ambience gas;

a pump or a compressor;

a pressure sensor for detecting the internal pressure of the vacuumchamber; and

a controller which controls the ambient gas flow rate control valve inresponse to the results of the measurement by the pressure sensor;

the ambient gas recirculating system comprises a tank for storing theambience gas exhausted by the pump or compressor, and a flow ratecontrol portion, and recirculates the ambient gas stored in the tankinto the sealed vacuum chamber at a predetermined flow rate through theflow rate control portion; and

the high pressure ambient gas recirculating system comprises: a highpressure tank for storing the ambient gas exhausted by the pump orcompressor and then highly compressed; and a regulator whichrecirculates the high pressure ambient gas to the sealed vacuum chamberwhile allowing the gas to decompress;

a valve is placed on both the upstream and downstream sides of at leastone of the tank and high pressure tank;

when the processing apparatus is stopped; the valve on the downstreamside of the tank is closed, the ambient gas is sent into the tank byactivating the pump or compressor; and then, the valve on the upstreamside of the tank is closed to keep the ambience gas stored in the tank;

at least one of the ambient gas recirculating system and high pressureambient gas recirculating system is provided with a bypass to the sealedvacuum chamber;

wherein the processing apparatus is stopped, the recirculating system isopened to the bypass, and the ambient gas is stored in the recirculatingsystem and bypass;

at least one of the ambient gas recirculating system and high pressureambience gas recirculating system is provided with a chemical filter,which is located where the ambient pressure is equal to, or greaterthan, the atmospheric air pressure;

at least one of the ambient gas recirculating system and high pressureambient gas recirculating system is provided with a temperature controlportion for adjusting the temperature of the ambient gas;

a sensor for measuring the temperature of the ambient gas is disposed atthe intake orifice, and the temperature control portion is controlled inresponse to the results of the measurement by the sensor;

a portion of the ambient gas recirculating system which exhausts theambient gas in the sealed vacuum chamber is constituted of two ambientgas recirculating branches, and a valve for controlling the ambient gasflow rate is connected into the branch with the smaller flow rate;

the processing portion contained in the sealed vacuum chamber is anexposing apparatus for substrate exposure.

The sixth processing apparatus in accordance with the present inventionfor accomplishing one of the aforementioned object is characterized inthat it comprises:

a sealed vacuum chamber which contains a processing portion;

an ambient gas recirculating system which exhausts the ambient gas inthe sealed vacuum chamber, increases the pressure of the exhaustedambient gas, and recirculates the exhausted ambient gas with the higherpressure back into the sealed vacuum chamber, with the use of acompressor or a pump;

wherein the ambient gas recirculated by the recirculating system isblown into the sealed, vacuum chamber so that a gas flow is generated ina predetermined direction, adjacent to the measuring portion.

Regarding the above processing apparatus, it is desired that therecirculating system is provided with a chemical filter, which islocated where the ambient pressure is equal to, or greater than, theatmospheric air pressure.

Further, according to another aspect of the present invention foraccomplishing one of the aforementioned object, a device manufacturingmethod, a device manufacturing method is characterized in that itemploys the above described first, second, third, fourth, fifth or sixthprocessing apparatus in accordance with the present invention.

According to the primary aspect of the present invention, a processingapparatus comprises: a sealed vacuum chamber which contains a processingportion; a pressure controlling system which keeps the internal pressureof the sealed vacuum chamber constant at a predetermined level byexhausting the ambient gas in the sealed vacuum chamber; and an ambientgas recirculating system which recirculates the ambient gas exhaustedfrom the sealed vacuum chamber back into the sealed vacuum chamber;wherein the ambient gas recirculated by the ambient gas recirculatingsystem is blown into the sealed vacuum chamber so that a gas flow isgenerated in a predetermined direction along the aforementionedprocessing portion. Therefore, the heat or the like generated by theheat sources in the sealed vacuum chamber is sufficiently removed byheat dissipation, preventing the internal temperature of the sealedvacuum chamber from becoming locally uneven. Thus, the ambient gas inthe sealed vacuum chamber is prevented from becoming turbulent.Consequently, the ambient gas in the sealed vacuum chamber remainsstable.

Further, with the use of a vacuum pump as the means for driving theambient gas in the ambient gas recirculating system, vibration such asthe one caused by the blower of a conventional air conditioner does notoccur, reducing the overall amount of the vibration, improving thereforethe apparatus in terms of resolution. Further, the employment of avacuum pump saves space, which reduces the apparatus cost. Also,providing the ambient gas recirculating system in a processing apparatuswith ordinary filters or chemical filters makes it possible toefficiently remove the particles in the ambient gas, or substancesproduced through chemical reaction triggered among the elements in theambient gas by exposure light. Therefore, exposure energy is preventedfrom attenuating, preventing thereby the throughput of the apparatusfrom reducing, as well as preventing uneven exposure.

Therefore, application of the present invention to a semiconductorexposing apparatus makes it possible to more precisely control thepressure of the ambient gas in a vacuum chamber as an exposing chamber,preventing exposing light such as X-ray from attenuating, preventinguneven exposure, preventing a mask or a substrate from beinginaccurately positioned due to heat, reducing the possibility ofmeasurement error, and improving positioning accuracy and alignmentaccuracy. Therefore, highly accurate exposure is possible. In addition,application of the present invention to a measuring apparatus makes itpossible to very accurately measure an object, that is, without thepossibility of measurement error.

Further, according to another aspect of the present invention, aprocessing apparatus comprises: a sealed vacuum chamber which contains aprocessing portion; a pressure controlling system which keeps theinternal pressure of the sealed vacuum chamber constant at apredetermined level by exhausting the ambient gas in the sealed vacuumchamber; and an ambient gas recirculating system which recirculates theambient gas exhausted from the sealed vacuum chamber, back into thesealed vacuum chamber; and a high pressure ambient gas recirculatingsystem which increases the pressure of the ambient gas exhausted fromthe sealed vacuum chamber, and recirculates this ambient gas with theincreased pressure into the sealed vacuum chamber. In this processingapparatus, an additional supply of fresh ambient gas is added to theambient gas recirculating system from an ambient gas supply source otherthan the ambient gas supply source, vacuum pump for operating a suctionchuck, high pressure tank connected to the high pressure ambient gasrecirculating system, and the like, which belong to the aforementionedambient gas recirculating system. Therefore, the pressure decrease whichoccurs in the sealed vacuum chamber and the ambient gas recirculatingsystem as the ambient gas is exhausted by the vacuum pump for holding asubstrate by suction is effectively compensate for. Thus, the internalpressure of the sealed vacuum chamber is controlled with improvedaccuracy.

Further, according to another aspect of the present invention, aprocessing apparatus comprises: a sealed vacuum chamber which contains aprocessing portion; a pressure controlling system which keeps theinternal pressure of the sealed vacuum chamber constant at apredetermined level by exhausting the ambient gas in the sealed vacuumchamber; and an ambience gas recirculating system which recirculates theambient gas exhausted from the sealed vacuum chamber, back into thesealed vacuum chamber; and a high pressure ambient gas recirculatingsystem which increases the pressure of the ambient gas exhausted fromthe sealed vacuum chamber, and recirculates this ambient gas with theincreased pressure into the sealed vacuum chamber. In this processingapparatus, when the apparatus is stopped for maintenance or the like, atleast a certain portion of the ambient gas is stored in the ambient gasrecirculating system and/or the high pressure ambient gas recirculatingsystem, in particular, in the high pressure tanks of the recirculatingsystems. In other words, the ambient gas is not entirely discharged intothe atmospheric air. With this arrangement, the consumption of theambient gas, that is, helium gas or the like, which is rather expensive,is greatly reduced, making it possible to greatly reduce the cost forrunning the apparatus.

Further, according to another aspect of the present invention, aprocessing apparatus comprises: a sealed vacuum chamber which contains aprocessing portion: and an ambient gas recirculating system whichexhausts the ambient gas in the sealed vacuum chamber, increases thepressure of the exhausted gas, and recirculates it into the vacuumchamber, with the higher pressure back into the sealed vacuum chamber,with the use of a compressor or a pump. In this apparatus, a means formeasuring the distances among the components in the sealed vacuumchambers, and the amounts of their shifts, is disposed in the sealedvacuum chamber. In operation, the ambient gas recirculated by saidambience gas recirculating system is blown into said sealed vacuumchamber so that a gas flow is generated in a predetermined directionalong the aforementioned processing portion, preventing the internaltemperature of the sealed vacuum chamber from locally becoming uneven,preventing thereby the ambient gas becoming locally turbulent.Therefore, the ambient gas in the sealed vacuum chamber remains stable,eliminating the possibility of measurement error of the measuring means.This apparatus further comprises a chemical filter, which is connectedinto the ambient gas recirculating system, at a point where the pressureof the ambient gas is higher compared to the other portions of theambient gas recirculating system. Therefore, it is possible toeffectively remove the particles in the ambient gas, and the substancesproduced in the ambient gas through the chemical reactions among theelements in the ambient gas.

These and other objects, features and advantages of the presentinvention will become more apparent upon a consideration of thefollowing description of the preferred embodiments of the presentinvention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention and,together with the description, serve to explain the principle of theinvention.

FIG. 1 is a schematic view of an embodiment of the present invention inthe form of a processing apparatus, that is, a semiconductor exposingapparatus.

FIG. 2 is a schematic view of another embodiment of the presentinvention in the form of a processing apparatus, that is, asemiconductor exposing apparatus.

FIG. 3 is a schematic view of an embodiment of the present invention inthe form of a measuring apparatus for a processing apparatus inaccordance with the present invention

FIG. 4 is a schematic view of the gas temperature controlling devicewhich keeps constant the temperature of the gas blown into the distancemeasuring path of the laser interferometry based measuring device in aprocessing apparatus in accordance with the present invention.

FIG. 5 is a schematic view of another embodiment of the presentinvention in the form of a processing apparatus, that is, asemiconductor exposing apparatus.

FIG. 6 is a schematic view of a portion of the system for compensatingfor the pressure decrease in the tank in the processing apparatusillustrated in FIG. 5.

FIG. 7 is a schematic view of another embodiment of the presentinvention in the form of a processing apparatus, that is, an exposingapparatus.

FIG. 8 is a schematic view of another embodiment of the presentinvention in the form of a processing apparatus, that is, an exposingapparatus.

FIG. 9 is a schematic view of another embodiment of the presentinvention in the form of a processing apparatus, that is, an exposingapparatus.

FIG. 10 is a schematic view of another embodiment of the presentinvention in the form of a processing apparatus, that is, an exposingapparatus.

FIGS. 11(a) and (b), are schematic views of the exhaust line portions oftwo different embodiments of the present invention in the form of aprocessing apparatus.

FIG. 12 is a flow chart for a semiconductor device manufacturingprocess.

FIG. 13 is a flow chart for a wafer process.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will now be described indetail in accordance with the accompanying drawings.

Referring to FIG. 1, an embodiment of the present invention will bedescribed. FIG. 1 is a schematic view of an embodiment of the presentinvention in the form of a processing apparatus, that is, asemiconductor exposing apparatus.

A referential character 4 designates a positioning stage equipped with asuction chuck 3. The positioning stage 4 is placed in a sealed vacuumcontainer 1 (hereinafter, “vacuum chamber”). The suction chuck 3 holds apiece of substrate 2 or wafer, with the use of suction. A referentialcharacter 6 designates a mask holding apparatus which holds a mask 5.Designated by a referential character 7 is a laser interferometry basedmeasuring device, which is used to measure the position of thepositioning stage 4. The positioning stage 4 which is holding thesubstrate 2 is accurately positioned based on the results of themeasurement by the laser interferometry based measuring device. Areferential character 8 designates a beam duct for guiding X-ray Remitted from an X-ray source (unillustrated) such as a synchrotron, intothe vacuum chamber 1 while maintaining an extremely high degree ofvacuum. A referential character 9 designates a beryllium window whichseparates the environment in the vacuum chamber 1 from the extremelyvacuum environment in the beam duct 8.

The laser interferometry based measuring device 7 for measuring theposition of the positioning stage 4 projects a laser beam emitted from alaser, onto mirrors 4 a and 6 a located on the positioning stage 4 andthe mask holding apparatus 6, respectively, The distance between themirrors 4 a and 6 a is measured by detecting the laser beam reflected bythe mirrors 4 a and 6 a, and based on the results of this measurement,the positioning stage 4 is moved to be accurately positioned. After thepositioning stage is accurately positioned, the X-ray R is guided intothe vacuum chamber 1 through the beam duct 8 and the beryllium window 9.Then, the X-ray R transfers the pattern of the mask 5 held by the maskholding apparatus 6, onto the substrate 2, or the wafer, attached to thesuction chuck of the positioning stage 4 by suction.

The system for controlling the internal low pressure ambience of thevacuum chamber comprises an exhaust gas line 11, a recirculatory supplyline 12, and a supply line branch 12A. The exhaust gas line 11 controlsthe internal pressure (degree of vacuum) of the vacuum chamber 1 byexhausting the ambient gas such as helium gas in the vacuum chamber 1with the use of a vacuum pump 20 (or compressor). The recirculatorysupply line 12 is connected to the exhaust gas line 11 to recirculatedthe gas into the vacuum chamber 1. The supply line branch 12A branchesfrom the recirculatory supply line 12 to send a portion of the gas fromthe vacuum chamber into the vacuum chamber 1. The vacuum chamber 1 isprovided with orifices 15 and 16 which are located in the top and bottomportions of the vacuum chamber, respectively. The orifice 15 is anintake orifice through which the gas which will become the ambient gasin the vacuum chamber is blown into the vacuum chamber. It is connectedto the recirculatory supply line 12. The orifice 16 is an exhaustorifice through which the ambient gas in the vacuum chamber 1 issuctioned out, or exhausted. It faces the orifice 15 across the vacuumchamber, and is connected to the exhaust gas line 11. Further, thevacuum chamber 1 comprises an auxiliary intake orifice 17 through whicha portion of the recirculating ambient gas from the vacuum chamber 1 isblown into the measurement light path of the laser interferometry device7.

The exhaust gas line 11 is provided with the vacuum pump 20 such as adry pump, a flow rate control valve 21, a controller 22, and a pressuresensor 23. THe vacuum pump 20 suctions to the ambient gas in the vacuumchamber 1 through the exhaust orifice 16 located in the bottom portionof the vacuum chamber 1. The flow rate control valve 21 is renderedadjustable in opening angle, and is used to control the flow rate atwhich the gas is allowed to flow through the exhaust gas line 11. Thepressure sensor 23 detects the internal pressure of the vacuum chamber1. The controller 22 adjusts the opening angle of the flow rate controlvalve 21 based on the output of the sensor 23, so that a proper amountof the ambient gas in the vacuum chamber 1 is exhausted by the vacuumpump 20 to control the internal pressure of the vacuum chamber 1.

The recirculatory supply line 12 is provided with a tank 26, a flow ratecontrol portion 27, and a temperature control unit 28, and is connectedto the intake orifice 15 within the vacuum chamber 1. The tank 26 storesthe gas exhausted and compressed by the vacuum pump 20. It suppressesthe pressure fluctuation caused by the pulsing or the like of the vacuumpump 20, and also functions as a buffer so that even if the amount ofthe gas which flows into the tank 26 through the flow rate control valve21 and the vacuum pump 20 reduces, the flow rate at which the gas issent into the vacuum chamber 1 is kept constant. The temperature controlunit 28 controls the gas temperature. The flow rate control portion 27is constituted of a mass flow controller, a conductance valve, or thelike, and recirculates the gas, the temperature of which has beenadjusted to a predetermined temperature by the temperature control unit28, into the vacuum chamber 1 through the intake orifice 15, at apredetermined flow rate. The supply line branch 12A branches from therecirculatory supply line 12 and is connected to the exhaust orifice 17.The gas which flows through the recirculatory supply line 12 ispartially diverted into this recirculatory supply line branch 12A, andthen is blown into the measurement light path of the laserinterferometry based measuring device 7 through the auxiliary intakeorifice 17.

The operation of the above described system which controls the vacuumenvironment in the vacuum chamber 1 is as follows. The vacuum pump 20suctions out the ambient gas, such as helium gas, in the vacuum chamber1 through the exhaust orifice 16. More specifically, the controller 22adjusts the opening angle of the flow rate control valve 21 in responseto the internal pressure of the vacuum chamber 1 detected by thepressure sensor 23, controlling thereby the amount by which the ambientgas in the vacuum chamber 1 is exhausted, so that the internal pressureof the vacuum chamber 1 is kept constant at a predetermined pressure(for example, 20,000 Pa). The gas exhausted from the vacuum chamber 1 bythe vacuum pump 20, and compressed to an approximate pressure of 102,000Pa by the vacuum pump 20, is stored in the tank 26 connected into therecirculatory supply line. The flow rate control portion 27 keepsconstant (for example, 500 SLM) the rate at which the gas is allowed toflow through the recirculatory supply line 12, so that the gas is blowninto the vacuum chamber 1 at a predetermined rate through the intakeorifice 15.

The gas blown into the vacuum chamber through the intake orifice 15flows downward toward the exhaust orifice 16 from the top portion of thevacuum chamber 1 along the substrate 2, mask 5, positioning stage 4, andthe like, in the vacuum chamber 1. This downward gas flow issubstantially parallel to the surfaces of the substrate 12 and mask 5.The heat generated by the heat sources, such as the driving means andelectrical wiring for the positioning stage in the vacuum chamber 1, canbe satisfactorily dissipated by this downward flow of the ambient gas inthe vacuum chamber 1, and then, is moved out of the vacuum chamber asthe ambient gas is exhausted. Consequently, the environment in thevacuum chamber 1 remains stable, preventing the mask 5 and substrate 2from being incorrectly placed due to heat. Therefore, the substrate 2 isprecisely exposed.

The recirculatory supply line branch 12A is configured so that the gas,the temperature of which has been adjusted to a predeterminedtemperature, can be blown into the measurement light path of the laserinterferometry based measuring device 7 at a velocity of no less than 1m/sec. With this arrangement, even if the ambient gas adjacent to theheat sources, that is, the driving means and electrical wiring for thepositioning stage 4, and the like, in the vacuum chamber 1 is warmed upby the heat sources, the warmed ambient gas is kept away from the lightpath of the laser interferometry based measuring device 7 by the gaslocally blown into the vacuum chamber 1 at a velocity substantiallygreater than the velocity at which the warmed gas rises. Therefore, theambient gas in the measurement light path of the laser interferometrybased measuring device is prevented from becoming turbulent. In otherwords, the state of ambient gas in the light path is kept constant,eliminating the possibility of the heat related measurement error. As aresult, the position of the positioning stage 4 is accurately measured.

From the viewpoint of the effect upon the circuit pattern, externaldeformation of the wafer surface, and the like, it is important that thegas to be blown into the adjacencies of the measurement light path ofthe laser interferometry based device and the wafer does not contain anyparticles. Therefore, the intake orifice 15 and the auxiliary intakeorifice 17 are fitted with an ULPA filter (unillustrated) to remove theparticles in the gas.

When a vacuum pump, rather than a fan, is employed in the system forcontrolling the state of the environment in the vacuum chamber 1, thepressure difference created between the upstream and downstream sides ofthe vacuum pump when the vacuum pump is in operation is greater byseveral digits than the pressure difference created between the upstreamand downstream sides of a fan. Thus, even if the vacuum pump, avibration source, is placed far enough away from the vacuum chamber toisolate the vacuum chamber from the vibration, the gas can be flowedthrough the vacuum chamber at a sufficient velocity, and obviously,unlike the fan of a conventional air conditioner, the vacuum pump, beingplaced away from the vacuum chamber, does not vibrate the apparatusesand stages in the chamber.

The tube, or pipe, of the plumbing, through which the gas is blown intoa specific local area of the vacuum chamber to cool the area and removeparticles from the area, is long and narrow. Further, in some cases, thesize and length of plumbing pipe of the apparatus must be reduced toreduce the apparatus cost, and in other cases, they must be reduced dueto the restriction arising from the reduction in the vacuum chambersize. Even in these cases in which the plumbing pipe is long and narrow,the employment of a vacuum pump can create the gas flow with asufficient velocity in the vacuum chamber. Thus, a vacuum pump iscompatible with a laser interferometry based measuring device, into theadjacencies of which the gas must be blown at a velocity no less than 1m/sec. Further, a vacuum pump, along with the flow rate control portion,makes it possible to keep constant the rate at which the gas flowsthrough the system, and therefor, the rate at which the gas is browninto the beam path of the laser interferometry based measuring devicedoes not flucture, which in turn reduces measurement error. Also, thevacuum pump is suitable for blowing the gas into the wafer conveyancepath to prevent particles from adhering to a wafer.

Next, another embodiment of the processing apparatus in accordance withthe present invention will be described with reference to FIG. 2. FIG. 2is a schematic view of another embodiment the processing apparatus, thatis, a semiconductor exposing apparatus, in accordance with the presentinvention. In this embodiment, the components identical to those in thepreceding embodiment are given the identical referential characters, andtheir detailed descriptions are omitted here.

The aforementioned ULPA filter employed in the preceding embodiment canremove the particles in the gas, but cannot remove the substances suchas ammonium sulfate produced through chemical reaction triggered in theambient gas by the exposure light. These substances adhere to the maskor the like, causing the exposure energy to attenuate, reducing therebythe throughput as well as making the exposure light nonuniform, which inturn makes the line width of the pattern on the wafer nonuniform. Thus,in order to remove the substances such as ammonium sulfate producedthrough the chemical reaction among the elements in the ambient gas, thegas recirculation path is desired to be provided with a chemical filter.A chemical filter is composed of a mixture of activated charcoalparticles and pertinent chemicals. It removes microscopic amounts ofunwanted gases by absorbing them not only physically, but alsochemically. However, if it is placed in an environment in which theambient pressure is below the atmospheric pressure, the chemicals whichare parts of a chemical filter are sometimes caused to evaporate, whichdeteriorates its ability to remove the unwanted gases. Therefore, thelocation at which a chemical filter is placed in the gas recirculatingpath is desired to be where the ambient pressure is approximately thesame or higher than the atmospheric air pressure.

Thus, in this embodiment, a chemical filter 29 is placed at a locationbetween the temperature control unit 28 and the flow rate control unit27, being on the downstream side of the temperature control unit 28 asshown in FIG. 2. In other words, it is placed at a location where thepressure of the ambient gas, which had reached a pressure (for example,102,000 Pa) slightly higher than the atmospheric air pressure as theambient gas was compressed while being exhausted from the vacuum chamber1, has come down to a pressure (for example, 101,330 Pa) approximatelythe same as the atmospheric air pressure, due to the pressure loss whichoccurred to the gas while the gas was flowed through the pipes and thetemperature control unit 28. Alternatively, it is possible to providethe recirculatory path with an additional pressure control valve ororifice dedicated to reducing the pressure of the ambient gas to apressure substantially equal to the atmospheric air pressure, and placea chemical filter on the downstream side of this additional pressurecontrol valve or orifice.

By placing a chemical filter at a location in the recirculatory pathwhere the ambient gas pressure becomes approximately the same as theatmospheric air pressure, the substance produced through the chemicalreaction among the elements in the ambient gas can be removed withoutdeteriorating the chemical filter performance. Therefore, theattenuation of exposure light energy does not occur, and therefore,exposure light does not become nonuniform. Consequently, accurateexposure is possible.

Next, referring to FIG. 3, another embodiment of the processingapparatus in accordance with the present invention will be described.FIG. 3 is a schematic view of an embodiment of the processing apparatusin the form of a measuring apparatus for a processing apparatus inaccordance with the present invention. Also in this embodiment, thecomponents identical to those in the preceding embodiments will be givenreferential characters identical to those in the preceding embodiments,and their detailed descriptions will be omitted here.

This embodiment relates to an apparatus to be placed in the vacuumchamber 1 to measure the distances among the components and the amountsof the shifting of the components. The vacuum chamber 1 is filled withhelium gas or the like, as the vacuum chamber 1 in the precedingembodiments was. The internal pressure of this vacuum chamber 1 is onefifth the atmospheric air pressure. Also, a laser interferometry basedmeasuring device 47 and an object to be measure are placed in the vacuumchamber 1. The vacuum chamber 1 is provided with orifices 15 and 16which are located in the top and bottom portions of the vacuum chamber,respectively. The orifice 15 is an intake orifice through which the gaswhich will become the ambient gas in the vacuum chamber is blown intothe vacuum chamber. It is connected to a recirculatory supply line 12.The orifice 16 is an exhaust orifice through which the ambient gas inthe vacuum chamber 1 is suctioned out. It faces the orifice 15 acrossthe vacuum chamber, and is connected to an exhaust gas line 11. The gasblown into the vacuum chamber 1 through the intake orifice 15 flowsdownward toward the exhaust orifice 16 across the path of a laser beam49. The exhaust gas line 11 and recirculatory supply line 12 forrecirculating the ambient gas in the vacuum chamber 1 comprises acompressor (or vacuum pump) 50, a tank 26, a temperature control unit28, a chemical filter 29, and a flow rate control portion 27. Thecompressor 50 sends the gas, the pressure of which has been reduced toapproximately one fifth the atmospheric air pressure, into the tank 26by increasing the gas pressure to a pressure equal to or greater thanthe atmospheric air pressure. The temperature control unit 28 keeps thegas temperature at 23° C.±0.1° C. The chemical filter 29 removes oil,ammonia, sulfuric acid ions, nitric acid ions, and the like from the gasas the gas, the pressure and temperature of which have been adjusted bythe compressor and the temperature control unit 28, is passed throughthe filter 29. The flow rate control portion 27 controls the gas flow sothat the gas is recirculated into the vacuum chamber 1 at apredetermined rate.

The laser interferometry based measuring device 47 is operated in theambient gas, or helium gas, or helium gas, the pressure of which hasbeen reduced to approximately one fifth the atmospheric air pressure asdescribed above. When the laser interferometry based measuring device 47is operated, that is, when the position of the object 48 is measured byprojecting a laser beam 49 onto the object 48, in the above describedenvironment, the measurement error traceable to temperature fluctuationis approximately {fraction (1/40)} the measuring error which occurs whenthe position of the object 48 is measured in an environment, in whichthe ambient pressure is equal to the atmospheric air pressure. In otherwords, the position of the object 48 is measured with much higheraccuracy. Further, placing the chemical filter 29 at a location wherethe pressure of the ambient gas has been increased by the compressor 50or the like allows the chemical filter to function without losing itsperformance.

Next, referring to FIG. 4, another embodiment of the processingapparatus in accordance with the present invention will be described.FIG. 4 is a schematic view of a gas temperature controlling means whichkeeps constant the temperature of the gas ready to be blown into themeasurement light path, and its adjacencies, of a laser interferometrybased measuring device.

In FIG. 4, the gas temperature controlling means comprises a gastemperature controlling portion 42, a gas temperature control watercirculating apparatus 43, a pipe 43 a, a gas temperature control watertemperature control portion 44, and a temperature sensor 45. The gastemperature controlling portion 42, which adjusts the gas temperature,is disposed in the pipe 40 leading to the intake orifice, on theupstream side of a particle catching filter 41 which also is disposed inthe pipe 40. The pipe 43 a leading from the gas temperature controlwater circulating apparatus 43 is run through the gas temperaturecontrolling portion 42. After the temperature of the gas temperaturecontrolling water is adjusted by the gas temperature controlling watercirculating apparatus, the water is circulated through the gastemperature controlling portion 42, so that the temperature of the gasis adjusted while the gas is flowing through the gas temperaturecontrolling portion 42. The temperature sensor 45 for measuring thetemperature of the gas which is flowing through the end portion 40 a ofthe pipe 40 is disposed adjacent to the end portion 40 a. The gastemperature controlling water temperature control portion 44 controlsthe gas temperature controlling water circulating apparatus 43 inresponse to the gas temperature detected by the temperature sensor 45,so that the gas temperature controlling water with a predeterminedtemperature is circulated through the gas temperature controllingportion 42 at a predetermined flow rate, and the gas temperature iscontrolled to remain at a predetermined temperature while the gas ispassing through the gas temperature controlling portion. In other words,the temperature of the gas ready to be blown into the vacuum chamber ismeasure by the temperature sensor 45, and is maintained at apredetermined temperature (normal temperature) by controlling the gastemperature control portion 42 by the gas temperature controlling watertemperature control portion 44 in response to the results of themeasurement by the temperature sensor 45. With this arrangement, thetemperature of the gas blown into the measurement light path of aninterferometry based measuring device, and also into the adjacencies ofthe mask and wafer, can be maintained at a predetermined temperature(normal temperature). Further, in FIG. 4, referential characters 47 and47 a designate a laser interferometry based measuring device and a beamsplitter prism, respectively. A referential character 48 designates anobject such as a mirror, the position of which is measured. The objectto be measured is held on a positioning stage or the like.

With the arrangements described above, the gas temperature at the pointwhere the gas is blown from the intake orifice into the vacuum chambercan be kept constant at a predetermined temperature (normaltemperature). In other words, it is not affected by the pressure losswhich occurs as the gas is flowed through a filter at a high velocity,the pressure loss which occurs as the gas flows through pipes, and thefluctuation of the temperature of the pipe, which is caused by theambient temperature around the pipe. Further, by blowing the temperaturecontrolled gas into a local area, or the measurement light path of theinterferometry measuring device, at a high velocity prevents gasturbulence, which in turn reduces measurement error. Consequently, theaccuracy of the interferometry based measuring device can be improved,which in turn improves the accuracy in aligning the substrate with themask.

In this embodiment, the gas is blown into a local area, or themeasurement light path of the interferometry based measuring device asdescribed above. However, the location into which the gas is blown doesnot need to be limited to the measurement light path of theinterferometry based measuring device. The gas may be blown into variousother locations, for example, the adjacencies of the mask and wafer,which is obvious.

Next, referring to FIG. 5, another embodiment of the processingapparatus In accordance with the present invention will be described.FIG. 5 is a schematic view of a semiconductor exposing apparatus inaccordance with the present invention. In this embodiment of the presentinvention, the pressure loss which occurs in the vacuum chamber and theambient gas recirculating system is compensated for. In FIG. 5, thecomponents identical to those in the preceding embodiments illustratedin FIGS. 1 and 2 are given referential characters identical to those inthe preceding embodiments.

The semiconductor exposing apparatus in FIG. 5 comprises, like the onein the embodiment illustrated in FIG. 1, a vacuum chamber 1, apositioning stage 4, a mask holding apparatus 6, a beam duct 8, and aberyllium window 9. The positioning apparatus 4 comprises suction chuck3 for holding, by suction, a substrate 2 in the vacuum chamber 2. Themask holding apparatus 6 holds a mask 5. The beam duct 8 is guidingduct. In operation, the internal space of the beam duct 8 is kept in anextremely high vacuum state, and an X-ray R emitted from a synchrotron,or the like X-ray source (unillustrated), of an exposing means is guidedinto the vacuum chamber 1 through the beam duct 8. The beryllium window9 separates the environment in the vacuum chamber 1 from the extremelyvacuum environment in the beam duct 8. The vacuum chamber 1 contains aplurality of static pressure bearings 10 (only one of them isillustrated in FIG. 5) in addition to the mask holding apparatus andpositioning stage 4. The static pressure bearing 10 is used as theguiding mechanism for highly precisely positioning the mask holdingapparatus 6 and positioning stage in the vacuum chamber 1. Normally, airis used as the operational fluid for the static pressure bearing 10, butin this embodiment, helium gas or the like which is used as the ambientgas in the vacuum chamber 1 is employed. The static pressure bearing 10is connected to high pressure gas supplying line 13, and the operationalfluid, or helium or the like gas, is used in a highly compressed state.The high pressure gas supplying line 13 will be described later. Thesuction chuck 3 of the positioning stage 4 is connected to a vacuum pump3 a located outside the vacuum chamber 1. The substrate 2 is held to thesuction chuck 3 by the vacuum generated by the operation of the vacuumpump 3 a. As is evident from the above description, the semiconductorexposing apparatus in this embodiment is structured so that the X-ray Rguided into the vacuum chamber 1 through the beryllium window 9 by thebeam duct 8 transfers the pattern created by the mask 5 held by the maskholding apparatus 6 onto the substrate 2 held to the positioning stage 4through the suction chuck 3.

The system for controlling the internal low pressure ambience of thevacuum chamber comprises an exhaust gas line 11, a recirculatory supplyline 12, a high pressure gas supply line 13, and a constant flow ratesupply line 14. The exhaust gas line 11 controls the internal pressure(degree of vacuum) of the vacuum chamber 1 by exhausting the ambient gassuch as helium gas in the vacuum chamber 1 with the use of a vacuum pump20. The recirculatory supply line 12 is connected into the exhaust gasline 11 to recirculate the gas into the vacuum chamber 1. The highpressure gas supply line 13 is a gas supply line through which the gasfrom the vacuum chamber 1 is supplied, in the highly compressed state,to the plurality of the static pressure bearings 10 for the positioningstage 4 or the like. The constant gas supply line 14 is a gas supplyline through which very pure gas which will become the ambient gas ofthe vacuum chamber 1 is flowed into the vacuum chamber 1 at apredetermined constant flow rate. The vacuum chamber 1 is provided withorifices 15 and 16 which are located in the top and bottom portions ofthe vacuum chamber 1, respectively. The orifice 15 is an intake orificethrough which the recirculated ambient gas from the vacuum chamber 1 isblown into the vacuum chamber 1. It is connected into the recirculatingsupply line 12. The orifice 16 is an exhaust orifice through which theambient gas in the vacuum chamber 1 is suctioned out, or exhausted. Itfaces the orifice 15 across the vacuum chamber 1, and is connected tothe exhaust gas line 11. The exhaust gas line 11 and the recirculatingsupply line 12 are structured as those in the embodiment illustrated inFIG. 1. In other words, the exhaust gas line 11 is provided with thevacuum pump 20 such as a dry pump, a flow rate control valve 21, acontroller 22, and a pressure sensor 23. The vacuum pump 20 suctions outthe ambient gas in the vacuum chamber 1 through the exhaust orifice 16located in the bottom portion of the vacuum chamber 1. The flow ratecontrol valve 21 is rendered adjustable in opening angle, and is used tocontrol the rate at which the gas is allowed to flow through the exhaustgas line 11. The pressure sensor 23 detects the internal pressure of thevacuum chamber 1. The controller 22 adjusted the opening angle of theflow rate control valve 21 based on the output of the sensor 23, so thatthe ambient gas in the vacuum chamber 1 is exhausted at a proper flowrate by the vacuum pump 20 to control the internal pressure of thevacuum chamber 1.

The recirculatory supply line 12 is provided with a tank 26, a flow ratecontrol portion 27, and a temperature control unit 28, and is connectedto the intake orifice 15 within the vacuum chamber 1. The tank 26 storesthe gas exhausted and compressed by the vacuum pump 20. It suppressesthe pressure fluctuation caused by the pulsing or the like of the vacuumpump 20, and also functions as a buffer so that even if the flow rate atwhich the gas flows into the tank 26 through the flow rate control valve21 and the vacuum pump 20 reduces, the flow rate at which the gas issent into the vacuum chamber 1 is kept constant. The temperature controlunit 28 controls the gas temperature. The flow rate control portion 27is constituted of a mass flow controller, a conductance valve, or thelike, and recirculates the gas, the temperature of which has beenadjusted to a predetermined temperature by the temperature control unit28, into the vacuum chamber 1 through the intake orifice 15, at apredetermined flow rate. A chemical filter 29A is disposed between thetemperature control unit 28 and the flow rate control portion 27, beingon the downstream side of the temperature control unit 28.

The high pressure gas supply line 13 is provided with a compressor 61, ahigh pressure tank 26, a regulator 63, and a temperature control unit28B. The compressor 61 further comprises the gas exhausted andcompressed by the vacuum pump 20 so that the gas pressure increases to apredetermined level. The high pressure tank 62 stores the gas compressedby the compressor 61. The regulator 63 releases the high pressure gasstored in the high pressure tank 62, while allowing the highlycompressed gas to slightly decompress, so that the static pressurebearings 10 of the positioning stage and the like are supplied with theslightly decompressed gas at a constant flow rate. The temperaturecontrol unit 28B controls the gas temperature. The chemical filter 29Bis disposed between the temperature control unit 28B and the regulator63, that is, on the downstream side of the temperature control unit 28B.The constant rate gas supply line 14 is provided with a cylinder 24filled with very pure gas, and a control valve 25. It supplies thevacuum chamber 1 with gas such as helium or the like which will becomethe ambient gas in the vacuum chamber 1, at a constant flow rate (forexample, 0.8 SLM), to compensate for the air leak into the sealed vacuumchamber 1.

The tank 26 of the recirculatory supply line 12 is provided with apressure sensor 66, and is connected to a cylinder 64 through a controlvalve 65. The pressure sensor 66 detects the internal pressure of thetank 26, and the cylinder 64 stores the gas and functions as a gassupply source. The gas in the cylinder 64 is released into the tank 26through the control valve 65 which is opened or closed in response tothe internal temperature of the tank 26 detected by the pressure sensor66.

In this embodiment, the system for controlling the ambient gas in thevacuum chamber works in the following manner. The vacuum pump 20 such asa dry pump suctions out, or exhausts, the ambient gas such as helium gasin the vacuum chamber 1 through the exhaust orifice 16 and the flow ratecontrol valve 21. As the gas is suctioned out, or exhausted, by thevacuum pump 20, the flow rate control valve 21 is controlled by thecontroller 22 in response to the internal pressure of the vacuum chamber1 detected by the pressure sensor 23, so that the internal pressure ofthe vacuum chamber 1 remains at a predetermined pressure (for example,20,000 Pa). The gas exhausted by the vacuum pump 20 is compressed by thevacuum pump 20 so that the gas pressure reaches approximately 102,000Pa. Then, the compressed gas is stored in the tank 26 of therecirculatory supply line 12. The flow rate control portion 27 of therecirculatory supply line 12 allows the gas stored in the tank 26 to berecirculated or blown, into the vacuum chamber 1 at a virtually constantflow rate (for example, 300 SLM+α).

The gas blown into the vacuum chamber 1 through the intake orifice 15flows downward toward the exhaust orifice 16 from the top portion of thevacuum chamber 1, along the substrate 2, mask 5, positioning stage 4,and the like, of the exposing apparatus in the vacuum chamber 1. Theheat generated by the heat source, such as the driving means andelectrical wiring for the positioning stage in the vacuum chamber 1 canbe satisfactorily removed, or dissipated, by this downward flow of theambient gas in the vacuum chamber 1. Consequently, the mask 5 andsubstrate 2 are prevented from being incorrectly placed due to heat.Therefore, accurate exposure is possible.

The constant flow rate supply line 14 prevents the purity of the ambientgas in the vacuum chamber 1 from being reduced by the air leak into thevacuum chamber 1. More specifically, very pure ambience gas for thevacuum chamber 1 is supplied into the vacuum chamber 1 from the cylinder24 through the control valve 25 at a constant flow rate (for example,0.8 SLM) which is adjustable by controlling the opening angle of thecontrol valve 25.

As for the high pressure gas for the static pressure bearings 10 for thesubstrate positioning stage, mask holding apparatus, and the like, thegas suctioned out from the vacuum chamber 1 into the recirculatorysupply line 12 by the vacuum pump 20 is supplied to the static pressurebearings 10 through a high pressure gas supply line 13 which branchesfrom the recirculatory supply line 12. The gas from the recirculatorysupply line 12 is compressed by the compressor 61 so that its pressurereaches a predetermined level (6 kgf/cm²), and is stored in the highpressure tank 62 of the high pressure gas supply line 13. Then, the gasstored in the high pressure tank 62 is fed to the static pressurebearings 10 at a constant flow rate (for example, 10 SLM) after beingallowed to decompress by the regulator 63 so that is pressure comes down(from 6 kgf/cm²) to approximately 6 kgf/cm². With this arrangement, thepositioning stage 4 and the like are highly precisely positioned by thehigh pressure gas supplied to the static pressure bearings 10 of thepositioning stage 4 and the like. Further, the attenuation of theexposing light can be reduced without concern about the contamination ofthe ambient gas in the vacuum chamber 1. In addition, even if theinternal pressure of the vacuum chamber 1 is slightly increased by asmall amount of the high pressure gas which leaks from the staticpressure bearing 10, the internal pressure of the vacuum chamber 1remains constant at a predetermined pressure. More specifically, thepressure increase in the vacuum chamber 1 is detected by the pressuresensor 23, and the flow rate control valve 21 is adjusted in response tothe pressure detected by the pressure sensor 23. Then, a pertinentamount of the ambient gas in the vacuum chamber 1 is suctioned out bythe vacuum pump 20 to keep the internal pressure of the vacuum chamber 1constant at a predetermined level (for example, 20,000 Pa).

The tank 26 is connected to the cylinder 64 as the source for theambient gas for the vacuum chamber 1, through the control valve 65 whichopens or closes in response to the results of the measurement by thepressure sensor 66. The control valve 65 is structured so that it opensas the internal pressure of the tank 26 falls below, for example, 0.8kgf/cm², and closes as the internal pressure of the tank 26 rises above,for example, 1.0 kgf/cm². In other words, as the internal pressure ofthe tank 26 measured by the pressure sensor 66 falls below 0.8 kgf/cm²,the control valve 65 opens to allow the gas to flow from the cylinder 64into the tank 26, and as the internal pressure of the tank 26 risesabove 1.0 kgf/cm², the control valve 65 closes to stop the gas supply.With this arrangement, as the internal pressure of the tank 26decreases, the gas is supplied, as necessary, from the cylinder 64 tothe tank 26 so that the loss of the internal pressure of the tank 26 iscompensated by the new gas supply.

As described before, the positioning stage 4 is disposed within thevacuum chamber 1, and the substrate 2 is held to the suction chuck 3 ofthe stage 4 by the suction generated by the vacuum pump 3 a. Therefore,the ambient gas in the vacuum chamber 1 is suctioned out of the vacuumchamber 1, temporarily reducing the internal pressure of the vacuumchamber 1, each time the vacuum pump 3 a is operated to maintain thesuction which is holding the substrate 2 to the suction chuck 3. As thisprocess is repeated for a long period of time, the overall amount of theambient gas suctioned out of the vacuum chamber 1 becomes too large tobe compensated for by only the ambience gas for the vacuum chamber 1supplied through the constant flow rate supply line 14 for compensatingfor the air leak into the vacuum chamber 1. Further, the tank 26 failsto function as the buffer for controlling the flow rate of the gas whichis being recirculated toward the vacuum chamber 1. Thus, the internalpressure of the vacuum chamber 1 gradually decreases. As the internalpressure of the vacuum chamber 1 decreases, and the amount of the gasrecirculating through the recirculatory supply line 12 also decreases asdescribed above, it becomes impossible for the internal pressure of thevacuum chamber 1 to be maintained at the predetermined pressure. In thisembodiment, however, as the internal pressure of the tank 26 decreases,a fresh supply of the ambient gas for the vacuum chamber 1 is suppliedto the tank 26 from the cylinder 64, and then is supplied from the tank26 to the vacuum chamber 1 through the recirculatory supply line 12 atthe predetermined flow rate. Therefore, the internal pressure of thevacuum chamber 1 is prevented from decreasing below the predeterminedpressure. In other words, this embodiment improves the accuracy withwhich the internal pressure of the vacuum chamber 1 is controlled,reducing the amount of the attenuation of the exposure light such asX-ray or the like, which in turn prevents nonuniform exposure, makingextremely precise exposure possible.

Illustrated in FIG. 6 is a means different from the above described onefor more precisely maintaining the internal pressure of the tank 26 withwhich the recirculatory supply line 12 is provided. In FIG. 6, a tank 26is connected to a cylinder 64 as a gas supply source for the vacuumchamber 1, through a control valve 65 which is controlled to open orclose in response to the results of the measurement by a pressure sensor66. The tank 26 is also connected to an exhaust pump 67, which suctionsthe gas from the tank 26 through a control valve 68 controlled to openor close in response to the results of the measurement by the pressuresensor 66. The control valve 65 is structured to open as the internalpressure of the tank 26 decreases below, for example, 1.0 kgf/cm², andto close as the internal pressure of the tank 26 increases beyond, forexample, 1.0 kgf/cm², whereas the control valve 68 is structure to openas the internal pressure of the tank 26 increases beyond, for example,1.0 kgf/cm², and to close as the internal pressure of the tank 26decreases below, for example, 1.0 kgf/cm². In other words, as theinternal pressure of the tank 26 measured by the pressure sensor 66decreases below 1.0 kgf/cm², the control valve 65 is opened to supplythe gas from the cylinder 64 to the tank 26, restoring the internalpressure of the tank 26 to 1.0 kgf/cm². On the contrary, as the internalpressure of the tank 26 increases beyond 1.0 kgf/cm². the control valve65 is closed, and the control valve 68 is opened, to suck the gas fromthe tank 26 by the exhaust pump 67, restoring the internal pressure ofthe tank 26 to 1.0 kgf/cm². Connecting the tank 26 to the gas supplycylinder 64 and the gas exhaust pump 67 through the control valves 65and 68, respectively, makes it possible to keep constant the internalpressure of the tank 26, facilitating the control operation of the flowrate control portion 27 of the recirculatory supply line 12.Consequently, the flow rate at which the ambient gas for the vacuumchamber 1 is caused to flow into the vacuum chamber 1 is more preciselymaintained. In other words, the system illustrated in FIG. 6 moreeffectively prevents the pressure decrease in the vacuum chamber 1. Inother words, it improves the accuracy with which the internal pressureof the vacuum chamber 1 is controlled.

Next, referring to FIG. 7, another embodiment of the processingapparatus in accordance with the present invention will be described.Also in this embodiment, the components identical to those in thepreceding embodiment illustrated in FIG. 5 are given referentialcharacters identical to those in FIG. 5, and their detailed descriptionswill be omitted here.

This embodiment is different from the embodiment illustrated in FIG. 5in that high pressure gas is supplied to the tank 26 of a recirculatorysupply line 12 from the high pressure tank 62 of a high pressure gassupply line 13. More specifically, the tank 26 of the recirculatorysupply line 12 and the high pressure tank 62 of the high pressure gassupply line 13 are connected to each other by a pipe 71 provided with acontrol valve 72. The control valve 72 is controlled in response to theresults of the measurement of a pressure sensor 73 which measures theinternal pressure of the tank 26. The control valve 72 is structured toopen as the internal pressure of the tank 26 decreases below, forexample, 0.8 kgf/cm², and to close as the internal pressure of the tank26 increases beyond, for example, 1.0 kgf/cm². In other words, as theinternal pressure of the tank 26 measured by the pressure sensor 73decreases below 0.8 kgf/cm², the control valve 72 is opened to supplythe gas from the high pressure tank 62 to the tank 26. On the contrary,as the internal pressure of the tank 26 increases beyond 1.0 kgf/cm²,the control valve 72 is closed to stop supplying the tank 26 with thegas.

Thus, also in this embodiment, like the above described embodimentillustrated in FIG. 5, the ambient gas in the vacuum chamber 1 issuctioned out of the vacuum chamber 1, temporarily reducing the internalpressure of the vacuum chamber 1, each time the vacuum pump 3 a isoperated to maintain the suction which is holding the substrate 2 to thesuction chuck 3. As this process is repeated for a long period of time,the internal pressure of the vacuum chamber 1 gradually decreases. Inthis embodiment, however, as the internal pressure of the tank 26decreases below a predetermined value, high pressure gas is supplied tothe tank 26 from the high pressure tank 62, keeping constant the flowrate at which the gas is recirculated into the vacuum chamber 1 throughthe recirculatory supply line 12. Therefore, the internal pressure ofthe vacuum chamber 1 is prevented from decreasing. In other words, thisembodiment prevents the decrease in the internal pressure of the vacuumchamber 1, improving the accuracy with which the internal pressure ofthe vacuum chamber 1 is controlled.

Next, referring to FIG. 8, another embodiment of the processingapparatus in accordance with the present invention will be described.Also in this embodiment, the components identical to those in thepreceding embodiment illustrated in FIGS. 5 and 7 are given referentialcharacters identical to those in FIGS. 5 and 7, and their detaileddescriptions will be omitted here.

This embodiment is characterized in that a vacuum pump 3 a connected toa suction chuck 3 for holding a substrate 2 by suction is connected tothe recirculatory supply line 12, on the upstream side of a tank 26,with the use of a pipe 75. Thus, the ambient gas in the vacuum chamber 1suctioned out by the vacuum pump 3 a as the vacuum pump 3 a is operatedto hold the substrate 2 to the suction chuck 3, is introduced into therecirculatory supply line 12 through the pipe 75. With this arrangement,the ambient gas in the vacuum chamber 1 suctioned out by the vacuum pump3 a, that is, the very gas which is one of the essential causes of thedecreases in the internal pressure of the vacuum chamber 1, is directlyintroduced, through the pipe 75, into the recirculatory supply line 12,and then into the tank 26, increasing the flow rate at which the gas iscirculated through the recirculatory supply line 12. In other words,this embodiment makes it possible to keep constant the amount of theambient gas in the vacuum chamber 1 recirculated back into the vacuumchamber 1 through the recirculatory supply line 12, preventing theinternal pressure of the vacuum chamber 1 from decreasing. Consequently,it improves the accuracy with which the internal pressure of the vacuumchamber 1 is controlled.

Next, referring to FIG. 9, another embodiment of the processingapparatus in accordance with the present invention will be described.FIG. 9 is a schematic view of another embodiment of the processingapparatus, or a semiconductor exposing apparatus, in accordance with thepresent invention. In this embodiment, when the processing apparatus isnot in operation, the ambient gas in a vacuum chamber 1 is stored in therecirculatory system to reduce the consumption of the ambience gas forthe vacuum chamber 1 so that the cost for running the processingapparatus is reduced. The components in this embodiment identical tothose in the embodiments illustrated in FIGS. 1 and 5 are givenreferential characters identical to those in FIGS. 1 and 5, and theirdetailed descriptions will be omitted here.

In FIG. 9, like the embodiments illustrated in FIGS. 1 and 5, thesemiconductor exposing apparatus in this embodiment comprises a vacuumchamber 1, a positioning stage 4, a mask holding apparatus 6, a beamduct 8, and a beryllium window 9. The positioning apparatus 4 comprisesa suction chuck 3 for holding, by suction, a substrate 2, in the vacuumchamber 2. The mask holding apparatus 6 holds a mark 5. The beam duct 8is a guiding duct. In operation, the internal space of the beam duct 8is kept in an extremely high vacuum state, and an X-ray R emitted from asynchrotron, or the like an X-ray source (unillustrated), of an exposingmeans is guided into the vacuum chamber 1 through the beam duct 8. Theberyllium window 9 separates the environment in the vacuum chamber 1from the extremely high vacuum ambience in the beam duct 8. The vacuumchamber 1 contains a plurality of static pressure bearings 10 (only oneof them is illustrated in FIG. 9) in addition to the mask holdingapparatus and positioning stage 4. The static pressure bearing 10 isused as the guiding mechanism for highly precisely positioning the maskholding apparatus 6 and positioning stage in the vacuum chamber 1.Normally, air is used at the operational fluid for the static pressurebearing 10, but in this embodiment, helium gas or the like which is usedas the ambient gas for the vacuum chamber 1 is employed. The staticpressure bearing 10 is connected to a high pressure gas supplying line13, and the operational fluid, or helium gas, or the like, is used in ahighly compressed state. The suction chuck 3 of the positioning stage 4is connected to a vacuum pump 3 a located outside the vacuum chamber 1.The semiconductor exposing apparatus in this embodiment is structured sothat the X-ray R guided into the vacuum chamber 1 through the berylliumwindow 9 by the beam duct 8 transfers the pattern created by the mask 5held by the mask holding apparatus 6 onto the substrate 2 held to thepositioning stage 4 through the suction chuck 3.

The system for controlling the internal low pressure ambience of thevacuum chamber 1 comprises an exhaust gas line 11, a recirculatorysupply line 12, a high pressure gas supply line 13, and a constant flowrate supply line 14. The exhaust gas line 11 controls the internalpressure (degree of vacuum) of the vacuum chamber 1 by exhausting theambient gas such as helium gas in the vacuum chamber 1 with the use of avacuum pump 20. The recirculatory supply line 12 is connected into theexhaust gas line 11 to recirculated the exhausted gas into the vacuumchamber 1. The high pressure gas supply line 13 is a gas supply linethrough which the gas from the vacuum chamber 1 is supplied, in thehighly compressed state, to the plurality of the static pressurebearings 10 for the positioning stage 4 or the like. The constant gassupply line 14 is a gas supply line through which very pure ambient gasfor the vacuum chamber 1 is flowed into the vacuum chamber 1 at apredetermined constant flow rate. The vacuum chamber 1 is provided withorifices 15 and 16 which are located in the top and bottom portions ofthe vacuum chamber 1, respectively. The orifice 15 is an intake orificethrough which the recirculated ambient gas from the vacuum chamber 1 isblown into the vacuum chamber 1. It is connected to the recirculatorysupply line 12. The orifice 16 is an exhaust orifice through which theambient gas in the vacuum chamber 1 is suctioned out. It faces theorifice 15 across the vacuum chamber 1, and is connected to the exhaustgas line 11.

The exhaust gas line 11, recirculating supply line 12, high pressure gassupply line 13, and constant flow rate supply line 14 in this embodimentare structured as those in the embodiment illustrated in FIG. 5. Thevacuum pump 20 of the exhaust gas line 11 is open to the atmospheric airthrough a valve 81. The valve 81 is structured so that it normallyremains closed. When it is closed, the gas suctioned out of the vacuumchamber 1 is sent through the recirculatory supply line 12, whereas whenit is open, the ambient gas in the vacuum chamber 1 and therecirculatory supply line 12 is discharged into the atmospheric air. Therecirculatory supply line 12 in this embodiment comprises a valve 82,which is normally keep open, and a pipe 83, through which high pressurenitrogen gas or high pressure air can be introduced into therecirculatory supply line 12. The valve 82 and pipe 83 are located onthe downstream side of the tank 26. The high pressure gas supply line 13is provided with valves 84 and 85. The valve 84 is located on theupstream side of a high pressure tank 62, and is normally kept open. Thevalve 85 is located on the downstream side of the high pressure tank 62,being between the high pressure tank 62 and a regulator 63, and isnormally kept open. The intake orifice 15, recirculatory lines 12 and13, and the like, may be fitted with an ULPA filter so that theparticles contained in the ambient gas for the vacuum chamber 1 areremoved as the gas is sent into the vacuum chamber 1.

In the above described system which controls the vacuum environment inthe vacuum chamber 1, the vacuum pump 20 suctions out the ambient gas,such as helium gas, in the vacuum chamber 1 through the exhaust orifice16. More specifically, a controller 22 adjusts the opening angle of aflow rate control valve 21 in response to the internal pressure of thevacuum chamber 1 detected by a pressure sensor 23, controlling therebythe amount by which the ambient gas in the vacuum chamber 1 isexhausted, so that the internal pressure of the vacuum chamber 1 is keptconstant at a predetermined pressure (for example, 20,000 Pa). The gasexhausted from the vacuum chamber 1 by the vacuum pump 20 and thencompressed to increase its pressure to approximately 102,000 Pa by thevacuum pump 20 is stored in the tank 26 of the recirculatory supply line12. The flow rate control portion 27 of the recirculatory supply line 12keeps constant (for example, 300 SLM+α) the flow rate at which the gasis allowed to flow through the recirculatory supply line 12, so that thegas is blown into the vacuum chamber 1 at a predetermined flow ratethrough the intake orifice 15.

The gas blown into the vacuum chamber 1 through the intake orifice 15flows downward toward the exhaust orifice 16 from the top portion of thevacuum chamber 1 along the substrate 2, mask 5, positioning stage 4, andthe like, in the vacuum chamber 1. The heat generated by the heatsource, such as the driving means and electrical wiring for thepositioning stage, in the vacuum chamber 1 can be satisfactorilyremoved, or dissipated, by this downward flow of the ambient gas in thevacuum chamber 1. Consequently, the mask 5 and substrate 2 are preventedfrom being incorrectly placed due to heat. Therefore, accurate exposureis possible. The constant flow rate supply line 14 is provided with acontrol valve 25. It is a gas supply line through which highly pureambient gas for the vacuum chamber 1 is supplied from a gas cylinder 24to the vacuum chamber 1 to prevent the purity of the ambient gas in thevacuum chamber 1 from being decreased by the air leak into the vacuumchamber 1. More specifically, the opening angle of the valve 25 iscontrolled so that the ambient gas for the vacuum chamber 1 is suppliedto the vacuum chamber 1 at a constant flow rate (for example, 0.8 SLM).

As for the high pressure gas for the static pressure bearings 10 for thesubstrate positioning stage, mask holding apparatus, and the like, thegas suctioned out from the vacuum chamber 1 into the recirculatorysupply line 12 by the vacuum pump 20 is supplied to the static pressurebearings 10 through a high pressure gas supply line 13 which branchesfrom the recirculatory supply line 12. The gas from the recirculatorysupply line 12 is compressed by the compressor 61 so that its pressurereaches a predetermined level (6 kgf/cm²), and is stored in the highpressure tank 62 of the high pressure gas supply line 13. Then, the gasstored in the high pressure tank 62 is fed to the static pressurebearings 10 at a constant flow rate (for example, 10 SLM) after beingallowed to decompress by the regulator 63 so that its pressure comesdown (from 6 kgf/cm²) to approximately 5 kgf/cm². At this point in time,the valves 84 and 85 are both kept open. With this arrangement, thepositioning stage 4 and the like are highly precisely positioned by thehigh pressure gas supplied to the static pressure bearings 10 of thepositioning stage 4 and the like. Further, the attenuation of theexposing light can be reduced without concern about the contamination ofthe ambient gas in the vacuum chamber 1.

When the semiconductor exposing apparatus in this embodiment is stoppedfor maintenance or the like, several steps are taken before theapparatus is stopped. First, the control valve 25 of the constant flowrate supply line 14 is closed in order to stop supplying the very pureambient gas to the vacuum chamber 1. Also, the valve 82 of therecirculatory supply line 12 and the valve 85 of the high pressure gassupply line 82 are closed. Then, the gas present in the lines 12 and 13,on the downstream sides of the valves 82 and 85, respectively, and theambient gas in the vacuum chamber 1, are suctioned into the vacuum pump20, and then are compressed so that the gas pressure increases to 6kgf/cm² by the compressor 61, being forced to flow into the highpressure tank 62. After virtually all the gas from the lines 12 and 13,and the vacuum chamber 1, is compressed into the high pressure tank 62,the valve 84 is closed, and the compressor 61 is stopped. Through thisprocess, most of the ambient gas for the vacuum chamber 1 is stored inthe high pressure tank 62, in which the pressure of the ambient gas forthe vacuum chamber 1 is 6 kgf/cm². Next, the valve 81 is opened to openthe vacuum pump 20 to the atmosphere, and the gas remaining in thevacuum chamber 1, tank 26, and the like, is discharged into theatmosphere by the vacuum pump 20 until virtually all the gas in thevacuum chamber 1, tank 26, and the like is exhausted from them, andthen, the valve 81 is closed. Lastly, nitrogen gas having the samepressure as the atmosphere, or the atmospheric air, is introduced intothe recirculatory supply line 12 through the pipe 83, consequently intothe vacuum chamber 1, tank 26, exhaust gas line 11, and a part of thehigh pressure gas supply line 13, ending the preparation for stoppingthe apparatus. Next, the apparatus is stopped for carrying out necessarymaintenance and the like operations.

With the above arrangement, the ambient gas for the vacuum chamber 1,such as helium gas which is rather expensive, is almost entirely storedin the high pressure tank 62 so that it can be reused. In other words,the gas is not discharged into the atmosphere as it had been in the caseof the prior processing apparatus. Therefore, the consumption of theambient gas for the vacuum chamber 1, such as helium gas which isexpensive, is greatly reduced. Consequently, the cost for running theprocessing apparatus is greatly reduced.

Next, referring to FIG. 10, another embodiment of the processingapparatus in accordance with the present invention will be described.The components in this embodiment identical to those in the embodimentillustrated in FIG. 9 are given referential characters identical tothose in the FIG. 9, and their detailed description will be omittedhere.

In this embodiment, the recirculatory system is provided with a firstbypass line 93 and a second bypass line 96, in addition to an exhaustgas line 11, a recirculatory supply line 12, and a high pressure gassupply line 13. The first bypass line 93 is an auxiliary line which isconnected to the exhaust gas line 11 and the recirculatory supply line12. The second bypass line 96 is an auxiliary line which is connected tothe upstream end portion of the high pressure gas supply line 13 andanother point of the high pressure gas supply line 13, that is, a pointon the downstream side of a regulator 63. This embodiment is differentfrom the embodiment illustrated in FIG. 9 in that, when the processingapparatus is not in operation, the ambient gas for the vacuum chamber 1is stored in the recirculatory system which comprises these bypass lines93 and 96.

The exhaust gas line 11 through which the ambient gas in the vacuumchamber 1 is exhausted to control the internal pressure of the vacuumchamber 1 is provided with a vacuum pump 20 such as a dry pump, a flowrate control valve 21, a controller 22, a pressure sensor 23, and afirst three way valve 91. The vacuum pump 20 suctions out the ambientgas in the vacuum chamber 1 through an exhaust orifice 16 located in thebottom portion of the vacuum chamber 1. The flow rate control valve 21is a valve, the opening angle of which is adjustable. The pressuresensor 23 detects the internal pressure of the vacuum chamber 1. Thefirst three way valve 91 is disposed on the upstream side of the vacuumpump 20. In operation, the opening angle of the flow rate control valve21 is adjusted by the controller 22 in response to the output of thepressure sensor 23, so that the internal pressure of the vacuum chamber1 is controlled.

The recirculatory supply line 12, through which the ambience gas for thevacuum chamber 1 exhausted from the vacuum chamber 1 is recirculatedinto the vacuum chamber 1, is provided with a tank 26, a flow ratecontrol portion 27, a temperature control unit 28A, a chemical filter29A, and a second three way valve 92, and is connected to an intakeorifice 15. The tank 26 stores the gas exhausted from the vacuum chamber1 by the vacuum pump 20 of the exhaust gas line 11, and compressed bythe vacuum pump 20. It suppresses the pressure fluctuation caused by thepulsation or the like of the vacuum pump 20, and also function as abuffer so that even if the flow rate at which the gas flows into thetank 26 decreases, the flow rate at which the gas is sent into thevacuum chamber 1 remains at a predetermined level. The flow rate controlportion 27 is constituted of a mass flow controller or a conductancevalve, or the like, and controls the flow rate at which the ambient gassuctioned out of the vacuum chamber 1 is recirculated into the vacuumchamber 1 through the intake orifice 15, after its temperature isadjusted to a predetermined level by the temperature control unit 28A.

The high pressure gas supply line 13, which compresses the ambience gasexhausted from the vacuum chamber 1, and supplies this compressedambience gas to a plurality of static pressure bearings 10 in the vacuumchamber 1, is provided with a compressor 61, a high pressure tank 62, aregulator 63, a temperature control unit 28B, a chemical filter 29B, athird three way valve 94, and a fourth three way valve 95. Thecompressor 61 further compresses the gas exhausted by the vacuum pump 20so that the gas pressure increases to a predetermined level. The highpressure tank 62 stores the gas compressed by the compressor 61. Theregulator 63 allows the compressed gas from the high pressure tank 62 toslightly decompress, and supplies this slightly decompressed gas to thestatic pressure bearings 10 of the positioning stage and the like at apredetermined constant flow rate. The third three way valves 94 isdisposed on the upstream side of the compressor 61, and the fourth threeway valve 95 is disposed on the downstream side of the regulator 63. Thefirst bypass line 92 connects the first and second three way valves 91and 92, and the second bypass line 96 connects the third and fourththree way valves 94 and 95. The constant flow rate supply line 14 isprovided with a gas cylinder 24 filled with highly pure ambience gas forthe vacuum chamber 1, and a flow rate control valve 25. It is structuredto supply the vacuum chamber 1 with the ambient gas for the vacuumchamber 1 at a predetermined constant flow rate (for example, 0.8 SLM)to counter the air leak into the vacuum chamber 1 caused by the vacuumof the vacuum chamber 1.

When the first to fourth three way valves 91, 92, 93 and 94 are keptclosed to prevent the ambience gas from flowing through the first andsecond bypass lines 93 and 96, the recirculatory system in thisembodiment structured as described above to control the internalenvironment of the vacuum chamber 1 functions in the same manner as therecirculatory system in the above described embodiment illustrated inFIG. 9. In other words, the ambient gas in the vacuum chamber 1 issuctioned out through the exhaust gas line 11, and recirculated into thevacuum chamber 1 through the recirculatory supply line 12, so that theambient gas in the vacuum chamber 1 is caused to flow downward whilemaintaining the internal pressuring of the vacuum chamber 1 at apredetermined vacuum level. Also, the ambient gas in the vacuum chamber1 suctioned out by the vacuum pump 20 is recirculated through the highpressure gas supply line 13, which compresses the gas and supplies thecompressed gas to the static pressure bearings 10.

When the apparatus is stopped for maintenance or the like operations,the following procedure is carried out prior to the stopping of theapparatus. First, the control vale 26 of the constant flow rate supplyline 14 is closed to stop supplying the highly pure ambience gas for thevacuum chamber 1. Then, the second and fourth three way valves 92 and 95are turned to the positions for the maintenance or the like operations.Then, the ambient gas in the vacuum chamber 1, the gas in therecirculatory supply line 12, on the downstream side of the second threeway valve 92, and the gas in the high pressure gas supply line 13, onthe downstream side of the fourth three way valve 95, are suctioned outby the vacuum pump 20, and compressed into the tank 26 and the highpressure tank 62. After the gases are compressed into the tank 26 andthe high pressure tank 62, the first and third three valves 91 and 94are turned to the positions for the maintenance or the like operation,creating a first path and a second path. The first path runs from thevacuum pump 20 of the exhaust gas line 11, and returns to the vacuumpump 20, through the tank 26 of the recirculatory supply line 12, thesecond three way valve 92, the first bypass line 93, a pressure lossportion 97, and the first three way valve 91, in this order. The secondpath runs from the compressor 61 of the high pressure gas supply line13, and returns to the compressor 61, through the high pressure tank 62,the regulator 63, the fourth three way valve 95, the second bypass line96, and the third three way valve 94, in this order. In this state, thecompressor 61 operates until the internal pressure of the high pressuretank 62 reaches 6 kgf/cm², stopping as the pressure reaches 6 kgf/cm²,and begins operating as the pressure decreases below 6 kgf/cm²,operating until the pressure reaches 6 kgf/cm². Thus, the ambience gasfor the vacuum chamber 1, such as helium gas, which is rather expensive,is almost entirely stored in the first path comprising the first bypassline 93 and the tank 26, and the second path comprising the secondbypass line 96 and the high pressure tank 62. In other words, unlike inthe case of the processing apparatus prior to the present invention, itdoes not occur that the ambience gas for the vacuum chamber 1 isentirely discharged into the atmosphere. Also in this embodiment, thevacuum pump 20 and the compressor 61 can be kept in the operating statewhile the processing apparatus is not in operation. Therefore, theambient gas for the vacuum chamber 1 stored in the first and secondpaths can be immediately reused as the apparatus is restarted. Thus,according to this embodiment, the consumption of the ambient gas for thevacuum chamber 1, such as helium gas, which is rather expensive, can begreatly reduced, which in turn greatly can greatly reduce the cost forrunning the apparatus.

Next, referring to FIGS. 11, (a) and (b), another embodiment of theprocessing apparatus in accordance with the present invention will bedescribed. FIGS. 11, (a) and (b), are schematic views of the exhaust gasline of the processing apparatus in accordance with the presentinvention, and its modification, respectively.

In each of the preceding embodiments of the present invention, theexhaust gas line, through which the ambient gas in the vacuum chamber,such as helium gas, is exhausted to control the internal pressure of thevacuum chamber, comprises: a vacuum pump or compressor for sectioningout the ambient gas in the vacuum chamber 1; a flow rate control valve,the opening angle of which is adjustable; a pressure sensor fordetecting the internal pressure of the vacuum chamber; and a controller.In this embodiment, however, the vacuum pump and the exhaust gas lineare disposed as illustrated in FIGS. 11, (a) and (b), to improve thepressure control accuracy so that the internal pressure of the vacuumchamber is more precisely maintained at a predetermined level.

In FIG. 11, (a), an exhaust gas line 11, which is connected to a tank26, and through which the ambient gas in the vacuum chamber 1, that is,helium gas or the like, is suctioned out to control the internalpressure of the vacuum chamber 1, is branched into first and secondexhaust gas lines 11 a and 11 b, which are provided with vacuum pumps 20a and 20 b, respectively. The conductances of the exhaust gas lines 11 aand 11 b are preset. In the embodiment illustrated in FIG. 11, (a), theconductances are preset so that the flow rate at which the gas flowsthrough the exhaust gas line 11 b is smaller than the flow rate at whichthe gas flows through the exhaust line 11 b. For example, theconductances are preset so that when the gas flows through the exhaustgas line 11 a at a flow rate of 300 SLM, the gas flows through theexhaust gas line 11 b at approximately 10 SLM. The flow rate controlvalve 21, the opening angle of which is adjusted by the controller 22 inresponse to the internal pressure of the vacuum chamber 1 detected bythe pressure sensor 23, is connected into the exhaust gas line 11 b withthe smaller flow rate.

With the exhaust gas line 11 being structured as described above, theambient gas, that is, helium gas or the like, in the vacuum chamber 1 issuctioned out through both the exhaust gas lines 11 a and 11 b. The flowrate at which the gas is suctioned out of the vacuum chamber 1 isadjusted with the use of the flow rate control valve 21 of the exhaustgas line 11 b, which is controlled by the controller 22 in response tothe internal pressure of the vacuum chamber 1 detected by the pressuresensor 23, so that the internal pressure of the vacuum chamber 1 is keptat a predetermined vacuum level. On the other hand, the flow rate atwhich the gas is suctioned through the exhaust gas line 11 a is keptsubstantially constant. In other words, the internal pressure of thevacuum chamber 1 is adjusted by adjusting the flow rate at which the gasis suctioned through the exhaust gas line 11 b, and therefore, the flowrate at which the gas is suctioned out of the vacuum chamber 1 can bemore accurately controlled with the use of the flow rate control valve21.

In the system illustrated in FIG. 11, (a), the exhaust lines 11 a and 11b are provided with vacuum pumps 20 a and 20 b, respectively. However,the two exhaust gas lines 11 a and 11 b may be connected to a singlevacuum pump 20 as illustrated in FIG. 11, (b). Also in this case, theflow rate control valve 21 is connected to the exhaust gas line 11 bwith a smaller flow rate. Therefore, the flow rate at which the gas issuctioned out of the vacuum chamber 1 is controlled at a more preciselevel with the use of the flow rate control valve 21.

In other words, in the embodiments illustrated in FIGS. 11, (a) and (b),a portion of the exhaust gas line, through which the ambient gas, thatis, helium gas or the like, in the vacuum chamber 1 is suctioned out, isbranched into two lines, and a pressure control means constituted of aflow rate control valve is connected to the line with a smaller flowrate. Therefore, the flow rate at which the gas is suctioned out of thevacuum chamber 1 is controlled at a more precise level with the use ofthe flow rate control valve connected to the line with the smaller flowrate, which in turn keeps the internal pressure of the vacuum chamber 1constant at a more precise level.

Next, an embodiment of a device manufacturing method which employs theabove described processing apparatus in accordance with the presentinvention will be described.

FIG. 12 depicts the flow of the manufacture of a microscopic device(semiconductor chip such as IC or LSI, liquid crystal panel, CCD, thinfilm magnetic head, and like microscopic machine). In Step 1 (circuitdesigning), a device pattern is designed. In Step 2 (maskmanufacturing), a mask which has the designed device pattern ismanufactured. Meanwhile, in Step 3 (wafer manufacturing), wafer ismanufactured from silicon, glass, or the like material. Step 4 (waferprocessing) is called the pre-processing step, in which an actualcircuit is formed on a piece of the wafer manufactured in Step 4, usinglithographic technologies. Step 5 (assembling) is called thepost-processing step, in which a semiconductor device is assembled usingthe wafers manufactured in Step 4. It includes an assembling process(dicing, bonding), a packaging process (chip sealing), and the like. InStep 6 (inspection), tests are carried out to confirm the performance,durability, and the like, of the semiconductor chip assembled in Step 5.Then, the semiconductor device completed through the above processes isshipped (Step 7).

FIG. 13 depicts the detail of the aforementioned wafer process. In Step11 (oxidization), the surface of the wafer is oxidized. In Step 12(CVD), electrically insulative thin film is formed across the wafersurface. In Step 13 (electrode formation), electrodes are formed on thewafer by vapor deposition. In Step 14 (ion implantation), ions areimplanted in the wafer. In Step 15 (resist processing), resist is coatedon the wafer. In Step 16 (exposure), the circuit pattern, or the maskpattern, is transferred onto each of a plurality of precisely alignedand designated sections of the wafer surface. In Step 7 (development),the exposed water is developed. In Step 8 (etching), the developed waferis etched except for the portions covered with the resist. In Step 19(resist removed), the resist, which is no longer useful after theetching of the wafer, is removed. These steps are repeated to formmultiple layers of circuit patterns.

With the use of the above described device manufacturing method, ahighly integrated device, which was difficult to manufacture in thepast, can be economically manufactured.

As described above, according to the main aspect of the presentinvention, a processing apparatus is provided with a gas recirculatingsystem, which suctions out the ambient gas in the vacuum chamber, andrecirculates it into the vacuum chamber, to create gas flow in apredetermined direction in the vacuum chamber of the processingapparatus, along the processing portion, so that the heat generated bythe heat source in the vacuum chamber is sufficiently removed, ordissipated, to prevent the internal temperature of the vacuum chamberfrom becoming locally uneven. Therefore, the ambient gas in the vacuumchamber does not become turbulent. In other words, the state of theambient gas in the vacuum chamber remains stable.

According to another aspect of the present invention, a processingapparatus is provided with a vacuum pump as a means for moving theambient gas for the vacuum chamber through the gas recirculating system.This eliminates vibration such as is caused by the blower of aconventional air container, reducing the overall amount of thevibration, improving therefore the apparatus in terms of resolution.Further, the employment of a vacuum pump saves space, which reduces theapparatus cost.

According to another aspect of the present invention, the ambience gasrecirculating system in a processing apparatus is provided with ordinaryfilters or chemical filters. This makes it possible to efficientlyremove the particles in the ambience gas, or substances produced throughchemical reaction triggered among the elements in the ambience gas byexposure light. Therefore, exposure energy is prevented fromattenuating. In other words, the present invention prevents exposureenergy from attenuating, preventing therefore the throughput of theapparatus from reducing, as well as preventing uneven exposure.

Further, the ambience gas can be blown into local areas such as thelocation of the measurement light path of the interferometry measuringdevice, while keeping constant the temperature of the gas to be blown.This reduces the amount of measurement error of the interferometrymeasuring device, improving therefore the alignment accuracy.

Further, according to another aspect of the present invention, the gasfrom the source other than the primary gas recirculating system, thatis, the gas from the gas supply source, the gas from the high pressuretank connected to the high pressure gas recirculating system, and thegas from the vacuum pump for operating the suction chuck, are stored Inthe tank connected into the primary gas recirculating system forrecirculating the ambient gas exhausted from the vacuum chamber.Therefore, the pressure decrease which occurs to the internal ambienceof the vacuum chamber or the gas recirculating system is effectivelycompensated for, improving the accuracy with which the internal pressureof the vacuum chamber is controlled.

Further, according to another embodiment of the processing apparatus inaccordance with the present invention, when the apparatus is not inoperation, the ambience gas in the sealed low pressure chamber is storedin the ambient gas recirculating system which comprises tanks and bypasslines, greatly reducing the consumption of the ambient gas, such ashelium gas, which is rather expensive. Therefore, it costs less to runthe apparatus.

Application of the present invention to a semiconductor exposingapparatus makes it possible to more precisely control the pressure ofthe ambient gas in a vacuum chamber as an exposing chamber, preventingexposing light such as X-ray from attenuating, preventing unevenexposure, preventing a mask or a substrate from being inaccuracypositioned due to heat, reducing the amount of measurement error, andimproving positioning accuracy and alignment accuracy. Therefore, veryprecise exposure is possible. In addition, application of the presentinvention to a measuring apparatus makes it possible to very preciselymeasure an object, without measurement error.

While the invention has been described with reference to the structuresdisclosed herein, it is not confined to the details set forth and thisapplication is intended to cover such modifications or changes as maycome within the purposes of the improvements or the scope of thefollowing claims.

What is claimed is:
 1. A processing apparatus comprising: a sealed vacuum chamber which contains a processing portion; a pressure controlling system, connected to said sealed vacuum chamber, which keeps the internal pressure of said sealed vacuum chamber constant at a predetermined level by exhausting ambient gas from said sealed vacuum chamber; an ambient gas recirculating system, connected to said pressure controlling system and to said sealed vacuum chamber, which recirculates the ambient gas exhausted from said sealed vacuum chamber through said pressure controlling system back into said sealed vacuum chamber; and a high pressure ambient gas recirculating system, connected to said pressure controlling system and to said sealed vacuum chamber, which increases the pressure of the ambient gas exhausted from said sealed vacuum chamber through said pressure controlling system and which recirculates the ambient gas having an increased pressure to said sealed vacuum chamber.
 2. The processing apparatus according to claim 1 further comprising an ambient gas supply system for adding ambient gas to said sealed vacuum chamber.
 3. The processing apparatus according to claim 1, wherein said pressure controlling system comprises: an ambient gas flow rate control valve for controlling the flow rate of the ambient gas; a pump or a compressor; a pressure sensor for detecting the internal pressure of said sealed vacuum chamber; and a controller which controls said ambient gas flow rate control valve in response to the results of a measurement by said pressure sensor.
 4. The processing apparatus according to claim 1, wherein said ambient gas recirculating system comprises a tank for storing the ambient gas exhausted by said pressure controlling system, and a flow rate control portion, and recirculates the ambient gas stored in said tank to said sealed vacuum chamber at a predetermined flow rate through said flow rate control portion; and wherein said high pressure ambient gas recirculating system comprises a high pressure tank for storing high pressure ambient gas, which had been exhausted by said pressure controlling system and then highly compressed and a regulator which recirculates the high pressure ambient gas to said sealed vacuum chamber while allowing the gas to decompress.
 5. The processing apparatus according to claim 4, wherein said ambient gas recirculating system further comprises a control valve which controls the gas flow rate of said ambient gas recirculating system in response to the results of a measurement of a pressure sensor for measuring the internal pressure of said tank in said ambient gas recirculating system.
 6. The processing apparatus according to claim 5, wherein said control valve allows for the addition of ambient gas to said tank or allows for the suctioning of ambient gas from said tank.
 7. The processing apparatus according to claim 1, wherein a pump for activating a suction chuck contained in said sealed vacuum chamber is connected to said ambient gas recirculating system.
 8. The processing apparatus according to claim 1, wherein at least said ambient gas recirculating system or said high pressure ambient gas recirculating system or both are provided with a chemical filter, which is located at a position where the ambient pressure is equal to, or greater than, the atmospheric air pressure.
 9. The processing apparatus according to claim 1, wherein at least said ambient gas recirculating system or said high pressure ambient gas recirculating system is provided with a temperature control portion for adjusting the temperature of the ambient gas.
 10. The processing apparatus according to claim 9, wherein a sensor for measuring the temperature of the ambient gas is disposed at an intake orifice, and wherein said temperature control portion is controlled in response to the results of a measurement by said sensor.
 11. The processing apparatus according to claim 1, wherein a portion of said ambient gas recirculating system which recirculates the ambient gas to said sealed vacuum chamber is constituted of two ambient gas recirculating branches, and wherein a valve for controlling the ambient gas flow rate is connected to one of the two ambient gas recirculating branches which has a smaller flow rate.
 12. The processing apparatus according to claim 1, wherein the processing portion contained in said sealed vacuum chamber is an exposing apparatus for substrate exposure.
 13. A processing apparatus comprising: a sealed vacuum chamber which contains a processing portion; a pressure controlling system, connected to said sealed vacuum chamber, which keeps the internal pressure of said sealed vacuum chamber constant at a predetermined level by exhausting the ambient gas from said sealed vacuum chamber; an ambient gas recirculating system, connected to said pressure controlling system and to said sealed vacuum chamber, which recirculates the ambient gas exhausted from said sealed vacuum chamber through the pressure controlling system back into said sealed vacuum chamber; and a high pressure gas recirculating system, connected to said pressure controlling system and to said sealed vacuum chamber, which increases the pressure of the ambient gas exhausted from said sealed vacuum chamber and which recirculates the ambient gas having a high pressure into said sealed vacuum chamber; wherein during operation of said processing apparatus and upon cessation of said operation, at least a portion of the ambient gas is stored in at least said ambient gas recirculating system or said high pressure ambient gas recirculating system or both.
 14. The processing apparatus according to claim 13 further comprising an ambient gas supplying system for adding ambient gas to said sealed vacuum chamber.
 15. The processing apparatus according to claim 13, wherein said pressure controlling system comprises: an ambient gas flow rate control valve for controlling the flow rate of the ambient gas; a pump or a compressor; a pressure sensor for detecting the internal pressure of said vacuum chamber; and a controller which controls said ambient gas flow rate control valve in response to the results of a measurement by said pressure sensor.
 16. The processing apparatus according to claim 13, wherein said ambient gas recirculating system comprises a tank for storing the ambient gas exhausted by said pressure controlling system, and a flow rate control portion, and recirculates the ambient gas stored in said tank to said sealed vacuum chamber at a predetermined flow rate through said flow rate control portion; and wherein said high pressure ambient gas recirculating system comprises a high pressure tank for storing high pressure ambient gas, which had been exhausted by said pressure controlling system and then highly compressed and a regulator which recirculates the high pressure ambient gas to said sealed vacuum chamber while allowing the gas to decompress.
 17. The processing apparatus according to claim 16, wherein a valve is placed on both the upstream and downstream sides of at least said tank or high pressure tank or both.
 18. A processing apparatus according to claim 17, wherein ambient gas is stored in said tank or said high pressure tank or both by a process comprising the steps of: ceasing operation of said processing apparatus; closing said valve on the downstream side of said tank or said high pressure tank or both; directing ambient gas into said tank or said high pressure tank or both by activating said pressure controlling system; and then closing said valve on the upstream side of said tank or said high pressure tank or both.
 19. The processing apparatus according to claim 13, wherein at least said ambient gas recirculating system or said high pressure ambient gas recirculating system or both, are provided with a bypass to said sealed vacuum chamber.
 20. A processing apparatus according to claim 19, wherein ambient gas is stored in said ambient gas recirculating system or said high pressure ambient gas recirculating system and in said bypass by a process comprising the steps of: ceasing operation of said processing apparatus; and opening said ambient gas recirculating system or said high pressure ambient gas recirculating system to said bypass.
 21. The processing apparatus according to claim 13, wherein at least said ambient gas recirculating system or said high pressure ambient gas recirculating system or both, are provided with a chemical filter, which is located at a position where the ambient pressure is equal to, or greater than, the atmospheric air pressure.
 22. The processing apparatus according to claim 13, wherein at least said ambient gas recirculating system or said high pressure ambient gas recirculating system or both, are provided with a temperature control portion for adjusting the temperature of the ambient gas.
 23. The processing apparatus according to claim 22, wherein a sensor for measuring the temperature of the ambient gas is disposed at an intake orifice, and said temperature control portion is controlled in response to the results of a measurement by said sensor.
 24. The processing apparatus according to claim 13, wherein a portion of said ambient gas recirculating system which recirculates the ambient gas to said sealed vacuum chamber is constituted of two ambient gas recirculating branches, and wherein a valve for controlling the ambient gas flow rate is connected to one of the two ambient gas recirculating branches which has a smaller flow rate.
 25. The processing apparatus according to claim 13, wherein the processing portion contained in said sealed vacuum chamber is an exposing apparatus for substrate exposure.
 26. A processing apparatus comprising: a sealed vacuum chamber which contains a processing portion; an exhausting device, connected to said sealed vacuum chamber, for exhausting ambient gas from said sealed vacuum chamber; an ambient gas recirculating system, connected to said exhausting device and to said sealed vacuum chamber, which recirculates the ambient gas exhausted from said sealed vacuum chamber through said exhausting device back into said sealed vacuum chamber; a high pressure ambient gas recirculating system, connected to said exhausting device and to said sealed vacuum chamber, which increases the pressure of the ambient gas exhausted from said sealed vacuum chamber, through said exhausting device and which recirculates the ambient gas having an increased pressure to said sealed vacuum chamber; and a pressure control device, connected to said exhausting device and to said sealed vacuum chamber, which keeps the internal pressure of said sealed vacuum chamber constant at a predetermined level.
 27. A processing apparatus comprising: a sealed vacuum chamber which contains a processing portion; a pressure controlling system, connected to said sealed vacuum chamber, which keeps the internal pressure of said sealed vacuum chamber constant at a predetermined level by exhausting ambient gas from said sealed vacuum chamber; an ambient gas recirculating system, connected to said pressure controlling system and to said sealed vacuum chamber, which recirculates the ambient gas exhausted from said sealed vacuum chamber through said pressure controlling system back into said sealed vacuum chamber; and a high pressure ambient gas recirculating system, connected to said pressure controlling system and to said sealed vacuum chamber, which increases the pressure of the ambient gas exhausted from said sealed vacuum chamber through said pressure controlling system and which recirculates the ambient gas having an increased pressure to said sealed vacuum chamber; wherein a substrate is exposed in said sealed vacuum chamber.
 28. A device manufacturing method using the apparatus as defined in claim 27 comprising the step of developing the exposed substrate.
 29. A processing apparatus comprising: a sealed vacuum chamber which contains a processing portion; a pressure controlling system, connected to said sealed vacuum chamber, which keeps the internal pressure of said sealed vacuum chamber constant at a predetermined level by exhausting the ambient gas from said sealed vacuum chamber; an ambient gas recirculating system, connected to said pressure controlling system and to said sealed vacuum chamber, which recirculates the ambient gas exhausted from said sealed vacuum chamber through said pressure controlling system back into said sealed vacuum chamber; and a high pressure gas recirculating system, connected to said pressure controlling system and to said sealed vacuum chamber, which increases the pressure of the ambient gas exhausted from said sealed vacuum chamber and which recirculates the ambient gas having a high pressure into said sealed vacuum chamber; wherein during operation of said processing apparatus and upon cessation of said operation, at least a portion of the ambient gas is stored in at least said ambient gas recirculating system or said high pressure ambient gas recirculating system or both; and wherein a substrate is exposed in said sealed vacuum chamber.
 30. A device manufacturing method using the apparatus as defined in claim 29 comprising the step of developing the exposed substrate.
 31. A processing apparatus comprising: a sealed vacuum chamber which contains a processing portion; an exhausting device, connected to said sealed vacuum chamber, for exhausting ambient gas from said sealed vacuum chamber; an ambient gas recirculating system, connected to said exhausting device and to said sealed vacuum chamber, which recirculates the ambient gas exhausted from said sealed vacuum chamber through said exhausting device back into said sealed vacuum chamber; a high pressure ambient gas recirculating system, connected to said exhausting device and to said sealed vacuum chamber, which increases the pressure of the ambient gas exhausted from said sealed vacuum chamber, through said exhausting device and which recirculates the ambient gas having an increased pressure to said sealed vacuum chamber; and a pressure control device, connected to said exhausting device and to said sealed vacuum chamber, which keeps the internal pressure of said sealed vacuum chamber constant at a predetermined level; wherein a substrate is exposed in said sealed vacuum chamber.
 32. A device manufacturing method using the apparatus as defined in claim 31 comprising the step of developing the exposed substrate. 